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 A373587 #14 Dec 17 2024 08:44:04
%S A373587 2,5,6,7,8,11,13,15,17,18,19,20,21,23,24,28,29,31,32,33,37,39,41,43,
%T A373587 44,45,47,50,51,52,53,54,57,59,60,61,63,67,68,69,70,71,72,73,76,79,80,
%U A373587 83,84,87,89,92,93,96,97,98,99,101,103,107,109,110,111,112,113,116,117,123,124,125,127,128,129,130,131,132
%N A373587 Numbers k for which A373149(k) is odd, where A373149 is fully additive with a(2) = 1 and a(p) = prevprime(p) for odd primes p.
%C A373587 Numbers such that the number of their prime factors (with multiplicity, A001222) and their 3-adic valuation (A007949) have different parity.
%H A373587 Antti Karttunen, <a href="/A373587/b373587.txt">Table of n, a(n) for n = 1..10000</a>
%F A373587 {k | A001222(k)+A007949(k) == 1 (mod 2)}.
%t A373587 Select[Range[200], OddQ[PrimeOmega[#] - IntegerExponent[#, 3]] &] (* _Paolo Xausa_, Dec 17 2024 *)
%o A373587 (PARI) isA373587(n) = !A373585(n);
%Y A373587 Positions of odd terms in A373149, positions of 0's in A373585.
%Y A373587 Cf. A001222, A007949, A373586 (complement).
%K A373587 nonn,easy
%O A373587 1,1
%A A373587 _Antti Karttunen_, Jun 13 2024