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2:57 PM
$f(1 \ 000)+1$ works quite well with PFGW:

8273631704085440....0000000000000001 is composite: RES64: [BEDCCADA556094C9] (221.6781s+0.0279s).

For $f(n) \pm 1$ with $n \le 1 \ 000$ there are no more PRP's to be announced.
 
Wow, both types ? And upto $n=1\ 000$ ? Impressing !
 
Pre-sieve small factors with Pari/Gp and then 3-PRP test with PFGW. That's all.
 
Good job however. Let us invent another expression, hopefully not already done by someone !
 
Yeah! An expression with lots and lots primes please.
 
What abouth this ?
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Your results
status (?) n digits number
P 468 195 I(468)^2+I(468)+1<195> = 8193345517...73<195>
499 numbers not shown. Reasons: 435 times incompletely factored 32 times composite 32 times fully factored
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Your results
status (?) n digits number
PRP * 958 400 I(958)^2+I(958)+1<400> = 5264397989...21<400>
PRP * 1352 565 I(1352)^2+I(1352)+1<565> = 2532848604...51<565>
498 numbers not shown. Reasons: 447 times incompletely factored 10 times fully factored 41 times composite
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3:13 PM
Ok
 
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Your results
status (?) n digits number
PRP * 1518 634 I(1518)^2+I(1518)+1<634> = 6130639719...41<634>
PRP * 1556 650 I(1556)^2+I(1556)+1<650> = 4683456098...07<650>
PRP * 1563 653 I(1563)^2+I(1563)+1<653> = 3948147935...07<653>
PRP * 1861 778 I(1861)^2+I(1861)+1<778> = 1422417235...83<778>
496 numbers not shown. Reasons: 453 times incompletely factored 40 times composite 3 times fully factored
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appears to be a good generator !
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Your results
status (?) n digits number
PRP * 2788 1165 I(2788)^2+I(2788)+1<1165> = 4131540644...93<1165>
499 numbers not shown. Reasons: 450 times incompletely factored 47 times composite 2 times fully factored
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Now you have something you can compare with the PFGW-output. This time it is straight forward to search for the primes. Shall I do that or do you want to do that ?
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Your results
status (?) n digits number
PRP * 3238 1353 I(3238)^2+I(3238)+1<1353> = 5069769969...81<1353>
499 numbers not shown. Reasons: 453 times incompletely factored 44 times composite 2 times fully factored
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Composites without known factor :
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Your results
status (?) n digits number
C 229 96 I(229)^2+I(229)+1<96> = 1040804665...71<96>
C 238 99 I(238)^2+I(238)+1<99> = 6013769174...81<99>
C 286 119 I(286)^2+I(286)+1<119> = 6949606563...53<119>
C 288 120 I(288)^2+I(288)+1<120> = 4763331200...93<120>
C 320 134 I(320)^2+I(320)+1<134> = 1130107496...91<134>
C 331 138 I(331)^2+I(331)+1<138> = 4475564714...31<138>
C 352 147 I(352)^2+I(352)+1<147> = 2681197042...01<147>
C 356 149 I(356)^2+I(356)+1<149> = 1259591883...07<149>
@MartinHopf
 
This is an easy syntax for PFGW
 
Exactly !
 
3:35 PM
for(n=1,10000,q=fibonacci(n)^2+fibonacci(n)+1;if(ispseudoprime(q),print1(n,", ")));
1, 2, 3, 4, 5, 6, 8, 11, 16, 24, 36, 43, 56, 64, 72, 158, 190, 213, 326, 416, 468, 958, 1352, 1518, 1556, 1563, 1861, 2788, 3238, 5787, 7078
 
3:50 PM
FF 96 (show) (I(236)^2+I(236)+1)/721<96> = 916963804462443311227<21> · 5095161881213559243043<22> · 11964354360846459786302227<26> · 2177015302006330090219857661<28>
 
4:11 PM
no more PRP's for $n \le 20 \ 000$.
 
I think, you should continue with PFGW , although PARI/GP is quite fast as well upto this limit.
 
Of course. PFGW:
F(7078)^2+F(7078)+1 is 3-PRP! (0.1845s+0.0003s)
that was the last response we are now at $n=24603$.
WOW:
F(24837)^2+F(24837)+1 is 3-PRP! (2.5257s+0.0004s)
 
Great ! (How many digits ?)
 
Let us prove it with Pari/GP
? ispseudoprime(q)
time = 1min, 36,643 ms.
%5 = 1
? #digits(q)
time = 3 ms.
%6 = 10381
?
 
4:30 PM
I currently factor :
CF 228 95 I(228)^2+I(228)+1<95> = 13 · 19 · 1609522293...39<93>
2.5 seconds for 10k digits, what a performance !
CF 249 104 I(249)^2+I(249)+1<104> = 3 · 109 · 277 · 2629343451...69<99>
Do you want to factor this C99 with the quadratic sieve ?
@MartinHopf
BPSW-test passed !
 
No, in the meanwhile I tested for $n \le 29 \ 701$.
 
OK , more interesting anyway !
Let us guess when the next prime occurs : 35 700 is my estimate
 
4:48 PM
:) I guess one more hit below 100 000. My guess 78 401.
 
5:45 PM
@Mathphile Hi
 

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