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 A356438 #11 Aug 07 2022 22:10:38 %S A356438 1,2,3,4,5,6,7,9,10,11,12,13,14,15,17,19,20,21,22,23,25,26,28,29,30, %T A356438 31,33,34,35,37,38,39,41,42,43,44,46,47,49,51,52,53,55,56,57,58,59,61, %U A356438 62,63,65,66,67,68,69,70,71,73,74,76,77,78,79,82,83,85 %N A356438 Numbers k such that A309892(k) = k/gpf(k), where gpf = A006530. %C A356438 Note that A309892(k) <= k/gpf(k); these sequence lists k such that the equality holds. %C A356438 For k >= 2, k is a term if and only if k/gpf(k) < nextprime(gpf(k)), where nextprime = A151800. %H A356438 Jianing Song, <a href="/A356438/b356438.txt">Table of n, a(n) for n = 1..36902</a> (all terms <= 50000) %e A356438 15 is a term since the number of steps needed to reach 0 of the iteration x -> x - gpf(x) starting at 15 is 3: 15 -> 10 -> 5 -> 0, and 3 = 15/gpf(15). %o A356438 (PARI) isA356438(n) = if(n>1, my(p=vecmax(factor(n)[, 1])); n/p<nextprime(p+1), 1) %Y A356438 Other than 1, indices of 1 in A356428. %Y A356438 Includes A000040 and A001358 as subsequences. %Y A356438 Complement of A356441. %Y A356438 Cf. A309892, A006530 (gpf), A151800, A076563. %K A356438 nonn,easy %O A356438 1,2 %A A356438 _Jianing Song_, Aug 07 2022