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 A242416 #19 Feb 09 2025 08:11:39 %S A242416 12,18,20,24,28,40,44,45,48,50,52,54,56,60,63,68,72,75,76,80,84,88,92, %T A242416 96,98,99,104,108,112,116,117,120,124,132,135,136,140,144,147,148,150, %U A242416 152,153,156,160,162,164,168,171,172,175,176,180,184,188,189,192,200 %N A242416 Numbers whose prime factorization viewed as a tuple of nonzero powers is not palindromic. %C A242416 These are terms that appear in 2-cycles of permutation A069799. %C A242416 Complement of A242414. %H A242416 Alois P. Heinz, <a href="/A242416/b242416.txt">Table of n, a(n) for n = 1..10000</a> %e A242416 12 = p_1^2 * p_2^1 is present, as (2,1) is not a palindrome. %p A242416 q:= n-> (l-> is(n<>mul(l[i, 1]^l[-i, 2], i=1..nops(l))))(sort(ifactors(n)[2])): %p A242416 select(q, [$1..200])[]; # _Alois P. Heinz_, Feb 04 2022 %t A242416 Select[Range[200], !PalindromeQ[FactorInteger[#][[All, 2]]]&] (* _Jean-François Alcover_, Feb 09 2025 *) %o A242416 (Scheme, with _Antti Karttunen_'s IntSeq-library) %o A242416 (define A242416 (COMPLEMENT 1 A242414)) %Y A242416 Complement: A242414. %Y A242416 A subsequence of A059404, from which this differs for the first at n=23, as 90 = A059404(23) is not member of this sequence, as the exponents in the prime factorization of 90 = 2^1 * 3^2 * 5^1 form a palindrome, even though 90 is not a power of a squarefree number. %Y A242416 Cf. A069799. %K A242416 nonn %O A242416 1,1 %A A242416 _Antti Karttunen_, May 29 2014