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 A373385 #10 Jun 10 2024 16:09:07
%S A373385 1,6,7,8,13,15,19,20,27,31,33,36,37,42,43,44,48,49,50,51,56,61,64,67,
%T A373385 68,69,73,78,79,87,90,91,92,97,103,104,105,109,110,114,116,120,123,
%U A373385 125,127,133,139,140,141,151,152,157,159,160,162,163,164,169,170,177,181,186,188,189,193,195,198,199,211,212,213
%N A373385 Numbers k for which A059975(k) is a multiple of 3, where A059975 is fully additive with a(p) = p-1.
%C A373385 A multiplicative semigroup: if m and n are in the sequence, then so is m*n.
%H A373385 Antti Karttunen, <a href="/A373385/b373385.txt">Table of n, a(n) for n = 1..10000</a>
%o A373385 (PARI)
%o A373385 A059975(n) = {my(f = factor(n)); sum(i = 1, #f~, f[i, 2]*(f[i, 1] - 1)); };
%o A373385 isA373385(n) = !(A059975(n)%3);
%Y A373385 Cf. A059975.
%Y A373385 Subsequences that are formed by intersecting this sequence with other multiplicative semigroups: A373384, A373473, A373492, A373494.
%Y A373385 Cf. also A289142.
%K A373385 nonn
%O A373385 1,2
%A A373385 _Antti Karttunen_, Jun 06 2024