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 A353301 #11 Apr 11 2022 12:57:09 %S A353301 1,2,3,4,5,7,9,11,12,18,21,24,25,28,35,45,46,50,56,70,73,76,78,79,82, %T A353301 89,94,105,113,116,118,121,123,124,138,139,153,157,159,164,197,201, %U A353301 203,210,217,253,261,273,280,283,287,342,352,356,381,396,437,450,471 %N A353301 Numbers k such that A004394(k)+1 is prime. %C A353301 First differs from A306587 at n=11. %H A353301 Amiram Eldar, <a href="/A353301/b353301.txt">Table of n, a(n) for n = 1..300</a> %e A353301 1 is a term since A004394(1)+1 = 1+1 = 2 is prime. %t A353301 s = {}; abm = 0; k = 0; Do[ab = DivisorSigma[-1, n]; If[ab > abm, abm = ab; k++; If[PrimeQ[n + 1], AppendTo[s, k]]], {n, 1, 10^6}]; s %Y A353301 Cf. A004394, A072828, A306587, A353300, A353302. %K A353301 nonn %O A353301 1,2 %A A353301 _Amiram Eldar_, Apr 10 2022