cp's OEIS Frontend

A373476 Numbers k such that k, A001414(k) and A083345(k) are all multiples of 3, where A001414 is fully additive with a(p) = p, and A083345 is the numerator of the fully additive function with a(p) = 1/p.

%I A373476 #16 Jun 07 2024 14:50:13
%S A373476 19683,157464,275562,393660,511758,688905,747954,866052,984150,
%T A373476 1220346,1259712,1279395,1338444,1456542,1515591,1692738,1810836,
%U A373476 1869885,2165130,2204496,2283228,2342277,2401326,2460375,2637522,2814669,2873718,3050865,3109914,3149280,3168963,3228012,3346110,3641355,3700404,3818502
%N A373476 Numbers k such that k, A001414(k) and A083345(k) are all multiples of 3, where A001414 is fully additive with a(p) = p, and A083345 is the numerator of the fully additive function with a(p) = 1/p.
%C A373476 Numbers k such that A373474(k) = 1+A369658(k).
%C A373476 All terms are multiples of 19683 [= 3^9].
%H A373476 Antti Karttunen, <a href="/A373476/b373476.txt">Table of n, a(n) for n = 1..23455; terms less than 2^21</a>
%F A373476 a(n) = 3^9 * A373475(n).
%o A373476 (PARI)
%o A373476 A001414(n) = ((n=factor(n))[, 1]~*n[, 2]); \\ From A001414.
%o A373476 A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
%o A373476 isA373476(n) = (!(n%3) && !(A001414(n)%3) && !(A083345(n)%3));
%Y A373476 Intersection of A008585 and A373475.
%Y A373476 Setwise difference A373475 \ A369659.
%Y A373476 Cf. A001414, A083345, A369658, A369659, A373474.
%K A373476 nonn
%O A373476 1,1
%A A373476 _Antti Karttunen_, Jun 06 2024