Generalise perfect numbers
Let \$\sigma(n)\$ represent the divisor sum of \$n\$.
Perfect numbers are numbers whose divisor sum equals their double or \$\sigma(n) = 2n\$. For example, \$\sigma(6) = 12 = 2\times6\$
Superperfect numbers are numbers whose twice iterated divisor sum equals their doubl...
Self improving program
quine code-golf restricted-complexity
In this challenge you will write a program or function which when run will output a faster solution to this challenge.
Formally speaking: you will write a program or function, \$T_0\$, which takes an integer \$x\$ as input and outputs a...
Challenge
Create a function or program that, when given a number \$N\$ and a tuple of \$k\$ numbers \$(n_i)\$, returns the number of ways \$N\$ can be written as a sum of \$k\$ integers (\$x_1 + x_2 + ... + x_k\$) such that \$n_i \le x_i \le N\$.
The input format is not fixed. You can read and pa...
Powerful numbers are positive integers such that, when expressed as a prime factorisation:
$$a = p_1^{e_1} \times p_2^{e_2} \times p_3^{e_3} \cdots \times p_k^{e_k}$$
all exponents \$e_1, e_2, ...\$ are greater than or equal to \$2\$. Note that the exponents do not include zero exponents, as exam...
Print 0 to 100 without using characters 1,2,3,4,5,6,7,8,9 in your code.
Seperator of numbers can be comma, whitespace or newline.
Shortest code wins.
