This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A234540 #22 Aug 29 2021 12:01:06 %S A234540 1,22,25,118,414,2745,10623,63201,1039161,1693864,2285297,52962021, %T A234540 66998865,232974402,315796805,336125877,834972771,1233903294, %U A234540 1309750075,1617454215,2056836133,5455816485,8589896196,9030058217,10622144467,12324258770,33725308558 %N A234540 Nonprimes k that divide the sum of the nonprimes up to k. %C A234540 Standard heuristics suggest that this sequence is infinite. - _Charles R Greathouse IV_, Dec 29 2013 %e A234540 a(2) = 22 because 1 + 4 + 6 + 8 + 9 + 10 + ... + 22 = 176 and 176/22 = 8. %t A234540 s = 0; Do[If[PrimeQ[k], Continue[]]; s += k; If[Mod[s, k] == 0, Print[k]], {k, 10^10}] (* Gomez *) %t A234540 Select[Range[10^4], Not[PrimeQ[#]] && Divisible[Sum[Boole[Not[PrimeQ[m]]]m, {m, #}], #] &] (* _Alonso del Arte_, Dec 29 2013 *) %o A234540 (PARI) v=List([s=1]); forcomposite(n=4,1e9,if(s%n==0, listput(v,n)); s+=n); Vec(v) \\ _Charles R Greathouse IV_, Dec 29 2013 %Y A234540 Cf. A007506. %K A234540 nonn %O A234540 1,2 %A A234540 _Vicente Izquierdo Gomez_, Dec 27 2013 %E A234540 a(14)-a(27) from _Donovan Johnson_, Dec 30 2013