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 A373144 #6 May 26 2024 18:42:22 %S A373144 1,8,27,35,36,64,65,77,95,119,125,135,143,155,161,162,180,185,189,203, %T A373144 209,215,216,221,252,275,280,287,288,297,299,305,323,329,335,341,343, %U A373144 351,365,371,377,395,396,407,413,425,437,459,468,473,485,497,512,513,515,520,527,533,545,551,575,581,605,611,612,616 %N A373144 Numbers k such that both A003415(k) and A276085(k) are multiples of 3, where A003415 is the arithmetic derivative and A276085 is the primorial base log-function. %C A373144 This is a multiplicative semigroup; if m and n are in the sequence then so is m*n. %H A373144 Antti Karttunen, <a href="/A373144/b373144.txt">Table of n, a(n) for n = 1..10000</a> %e A373144 65 is present as A003415(65) = 18 = 3*6 and A276085(65) = 2316 = 3*772. %e A373144 77 is present as A003415(77) = 18 = 3*6 and A276085(77) = 240 = 3*80. %e A373144 5005 (= 65*77) is present as A003415(5005) = A276085(5005) = 2556 = 3*852. (See A369650). %o A373144 (PARI) \\ See A373143. %Y A373144 Cf. A003415, A276085, A373143 (characteristic function). %Y A373144 Intersection of A327863 and A339746. %Y A373144 Positions of multiples of 3 in A373145. %Y A373144 Cf. also A369650. %K A373144 nonn %O A373144 1,2 %A A373144 _Antti Karttunen_, May 26 2024