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 A274566 #39 Jun 09 2025 06:03:38 %S A274566 6,9,11,12,14,22,40,42,46,154,190,2656,6490,44650,318250,1360810, %T A274566 1503370,1788490,3214090,103712410,3915380170,6077111050,9796360330, %U A274566 10828121356,33086522327050,35966517350410,11577093570201610,16726040141635450,576460762503970816 %N A274566 Numbers k such that sigma(k) == 0 (mod k-10). %e A274566 sigma(11) mod (11 - 10) = 12 mod 1 = 0. %t A274566 k = -10; Select[Range[1, 10^7], # + k != 0 && Mod[DivisorSigma[1, #], # + k] == 0 &] (* _Vincenzo Librandi_, Jul 06 2016 *) %o A274566 (Magma) [n: n in [1..2*10^6] | n ne 10 and SumOfDivisors(n) mod (n-10) eq 0 ]; // _Vincenzo Librandi_, Jul 06 2016 %o A274566 (PARI) isok(k) = (k!=10) && !(Mod(sigma(k), k-10)); \\ _Michel Marcus_, May 30 2025 %Y A274566 Contains subsequence A223607. %Y A274566 Contains 2 * odd terms of A101223. %Y A274566 Cf. A045770, A067702, A088833, A181598, A274551, A274552, A274553, A274554, A274556, A274557, A274558, A274559, A274560, A274561, A274562, A274563, A274564, A274565. %K A274566 nonn %O A274566 1,1 %A A274566 _Paolo P. Lava_, Jul 06 2016 %E A274566 a(19)-a(24) from _Giovanni Resta_, Jul 06 2016 %E A274566 a(25)-a(26) from _Jud McCranie_, Dec 02 2019 %E A274566 Terms 6,9 inserted and a(27)-a(29) added by _Max Alekseyev_, May 30 2025