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 A340720 #14 Jan 17 2021 10:57:07
%S A340720 14,12,180,25908120
%N A340720 Least positive number k such that sigma(k) = n * sigma(k+1).
%e A340720 n | sigma(a(n)) | sigma(a(n)+1)
%e A340720 ----+-------------+--------------
%e A340720 1 | 24 | 24
%e A340720 2 | 28 | 14
%e A340720 3 | 546 | 182
%e A340720 4 | 103680000 | 25920000
%o A340720 (PARI) {a(n) = my(k=1); while(sigma(k)!=n*sigma(k+1), k++); k}
%Y A340720 Cf. A002961, A080372, A163193, A217791, A340715.
%K A340720 nonn,more,hard
%O A340720 1,1
%A A340720 _Seiichi Manyama_, Jan 17 2021