A342503 Numbers k such that k divides A340740(k).

1, 2, 3, 4, 6, 19, 48, 111, 4630, 5428, 13569, 41628, 87659, 108990, 555716, 751863, 973813, 5124585, 8663699, 19545678, 24330343

Offset: 1

Author

J. M. Bergot and Robert Israel, Mar 16 2021

Keywords

• nonn
• more

Examples

			a(8) = 111 is a term because 111 divides A340740(111) = 444.
		

Crossrefs

Cf. A340740.

Programs

Maple

filter:= proc(n) local k; add(`if`(igcd(k,n)=1, (n-k) mod k, 0),k=1..n/2) mod n = 0 end proc:
select(filter, [$1..10^5]);

Python

from math import gcd
A342503_list = [k for k in range(1,10**4) if sum(k % i for i in range(1,k//2+1) if gcd(i,k) == 1) % k == 0] # Chai Wah Wu, Mar 18 2021

Extensions

a(14)-a(17) from Chai Wah Wu, Mar 18 2021

a(18)-a(19) from Martin Ehrenstein, May 14 2021

a(20) from Kevin P. Thompson, Jan 19 2023

a(21) from Kevin P. Thompson, Feb 07 2023