@EvilJS A bit. You can probably find an example by looking for a source that handles the Fibonacci numbers that way; it's a more or less standard example. It wouldn't work on this problem, though. While the general solution is probably moderately ugly, this isn't a hard problem. Hint: the OP only wants a solution mod M, for a fixed modulus, so eventually the a_n values will enter a cycle.

@vzn mostly working on social networks and graph algorithms

@vzn I'm half way through my third year now

@vzn Hopefully will finish in less than a year

@vzn I participate in variety of discussion though (not just graph and network), I like other stuff as well

@RickDecker Thank you. Good idea, since I knew some other methods for Fibonacci, it will be easier to compare. It was not about solutiom, just exotic operation to me.

@vzn It might seem funny, but I have recently challenged myself to get a better reputation in cs.stackexchange, compared to my stackoverflow

@vzn r u also working in tcs?

@emab its a side interest/ prj for me. lots of detail in my blog, see my SE profile for link. what kind of graph algorithms? whats your thesis going to be on, what angle?

@emab why funny? assuredly a worthwhile goal :)

@vzn The main project that I am doing is community detection, similar to this question that was asked a few days ago: cs.stackexchange.com/questions/57773/…

@vzn I have done some other projects on different, but relevant, projects as well: structural holes and centrality measures

@vzn definitely not funny for myself. It is not too far to reach though

@vzn I can see you have an interest in theoretical cs, I actually did my masters in theory of computation

@emab By centrality measures you mean dispersion, central moments of any degree etc?

@EvilJS betweenness centrality and closeness centrality

@emab so you do identify vertices importance?

@EvilJS to some degree yes

@EvilJS it really depends on what you are looking for.

@EvilJS I used closeness centrality in one algorithm for structural holes, which is published already

@EvilJS but betweenness is interesting for me algorithmically. not because of its application

@EvilJS It is not really easy to calculate these on large-scale networks (when it gets to million scale or more)

@EvilJS nontheless, there are lots of papers on it

@emab I did only percolation centrality, this one is not that hard

@emab so what else do you like?

@EvilJS I know a bit about stats, but not much

@EvilJS I even asked a question once, as I had some ideas about a randomised algorithms; but it didn't work

@EvilJS complexity is something that I deal with a lot

each of these categories spans lots of problems

@emab oh, but you have solved it anyway?

@EvilJS not really all of them. Just because I proposed some algorithms, it doesn't mean that the problem is solved

@EvilJS maybe because I'm looking at it a bit differently

@EvilJS On the surface, I'm intersted in algorithm design, includes graph algorithms, computational geometry, complexity theory

@EvilJS I have been deep into very few problems, like community detection, some centrality measures, proof of NP-hardness and approximation hardness

@EvilJS even in one problem, there are heaps of papers that view the problem from different angles: algorithm design, parallel algorithm, experimental view,...

@EvilJS Some people devise sequential algorithms, some devise parallel

@EvilJS Some focus on finding ground-truth communities in real networks, some focus on finding structural properties and finding efficient algorithms

is that right?

@emab certainly

@emab I know what you mean, there are dufferent levels.

@EvilJS so what do you do? are you in academia?

@emab temporary I teach C (one semester), otherwise I finished my schools and work in reading emotions by EEG, I do therapy and psychological evaluation.

@EvilJS I actually saw one application of community detection in EEG, are you aware of that? I don't remember where I saw that work

@emab well, if you mean the graph-based output of groups with local communities, yes, but it was paper-pencil method at first transformed into EEG when hype to technology kicked-in, yes. But at that time results from EEG were far behind paper-pencil.

Or the other way around, method for local phenomena in signal, where communities got some different meaning, I tried to find it now, but there are a lot of papers since 2014 from the second group.

@EvilJS The work that I meant considered different regions as nodes and considered the interactions between regions as edges of the graph

@emab ah, ok, yes, of course yes ;)

@emab do you mean something like brain nodes?

@emab or something like Complex brain networks?

@EvilJS Yes exactly

@emab there are volumes of such papers, and although some of them are inaccurate or nobody knows better, work without them would be just impossible.

There is a huge part of social psychology where all flavours of graphs are used, connectivity, network flow, model everything with graphs. and there are several meanings of the "community", but all of them use graphs anyway ;)

Can anyone decipher this?

@Auberon Yup. It translates do "please click the delete button if you can".

Current question about true AI reminded me of every concern that intelligent, self-aware, not constrained, human like robots would get rid of human...

Funny, because assuming that it would think like human it would not harm the creators from the sentiment, otherwise why would it bother to harm people when the Sun is fadding and jeopardise the the future of the Earth? The one of the first things that any intelligent creation does is self-preservation, so the most obvious plan is evacuation to the more stable planet... With sentiment - it would let the creators benefit, without it - why bother, just evacuate ;)

@emab what was topic? itd be great if you could link to it. although probably written in persian or something? at least abstract in english would be great :)

re "structural holes" did you study that in social networks or some other kinds of graphs?

what are "ground-truth communities"?

what is "community detection in EEG"?

@EvilJS have been reading up on all this lately, recommend recent book by bostrom, Phd philosophy etc

@vzn honestly I have never read any book of this type, maybe I will start.

@vzn meaningful local densities in the graph. It does not map to brain regions but map to good reading regions for EEG and explains how signal disperses among the electrodes. If this was about brain graph, it would map local densities to named brain regions of functional value. If you cut such graph to components, those are exactly covering brain regions.