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 A379013 #7 Dec 13 2024 12:39:52 %S A379013 0,3,12,39,65,78,158,237,357,537,807,2152,17224,27560,45935,76560, %T A379013 229683,306244,382805,459366,918734,1063635,1294860,1371935,1421263, %U A379013 3150013,6300026,8721659,26164977,34234782,62763767,76711272,230133819,306845092,1227380372,1349400644 %N A379013 Positions of zeros in A378505. %C A379013 See Corneth's algorithm in A378505 for finding the terms of this sequence. %t A379013 A379013nxt[z_] := If[z == 0, 3, SelectFirst[Divisors[z*(z+1)], # > z+1 && Divisible[#*(#-1)/2 - z*(z+1)/2, #] &]]; %t A379013 NestList[A379013nxt, 0, 50] %Y A379013 Cf. A378505. %K A379013 nonn %O A379013 1,2 %A A379013 _Paolo Xausa_ and _David A. Corneth_, Dec 13 2024