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 A111360 #29 Jan 05 2020 06:00:45 %S A111360 1,2,3,9,21,129,5663,40087,184971,246901,251737,1610143,3098384123, %T A111360 19819945093,21323898091,123112069843,130057547087 %N A111360 Integers k such that sigma(k) + prime(k) is divisible by k. %C A111360 a(18) > 10^13, if it exists. - _Giovanni Resta_, Jan 05 2020 %e A111360 The divisors of 21 are 1,3,7,21 and the 21st prime is 73. 1+3+7+21+73 = 105, which is divisible by 21. %t A111360 Select[Range[10^8], Mod[Prime[ # ] + Plus @@ Divisors[ # ], # ] == 0 &] (* _Ray Chandler_, Jan 24 2006 *) %o A111360 (PARI) p=2; for(n=1,100000000, if( (sigma(n)+p) % n == 0, print(n) ) ; p=nextprime(p+1) ; ) \\ _R. J. Mathar_, Feb 11 2008 %Y A111360 Cf. A000203, A038607. %K A111360 nonn,more %O A111360 1,2 %A A111360 _Ray G. Opao_, Nov 07 2005 %E A111360 a(13)-a(15) from _Donovan Johnson_, Apr 22 2008 %E A111360 New name from _Michel Marcus_, Dec 10 2019 %E A111360 a(16)-a(17) from _Giovanni Resta_, Dec 12 2019