# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a349390 Showing 1-1 of 1 %I A349390 #11 Nov 21 2021 10:17:49 %S A349390 1,2,3,3,5,6,7,4,8,10,10,9,12,14,17,5,15,16,17,15,24,20,20,12,28,24, %T A349390 22,21,25,34,27,6,35,30,47,24,32,34,42,20,35,48,37,30,50,40,40,15,54, %U A349390 56,53,36,45,44,71,28,60,50,50,51,52,54,71,7,84,70,57,45,71,94,60,32,62,64,100,51,99,84,67,25,63,70,70 %N A349390 Dirichlet convolution of A126760 with Kimberling's paraphrases, A003602. %H A349390 Antti Karttunen, Table of n, a(n) for n = 1..20000 %F A349390 a(n) = Sum_{d|n} A126760(n/d) * A003602(d). %t A349390 f[n_] := 2 * Floor[(m = n/2^IntegerExponent[n, 2]/3^IntegerExponent[n, 3])/6] + Mod[m, 3]; k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, f[#] * k[n/#] &]; Array[a, 100] (* _Amiram Eldar_, Nov 16 2021 *) %o A349390 (PARI) %o A349390 A003602(n) = (1+(n>>valuation(n,2)))/2; %o A349390 A126760(n) = {n&&n\=3^valuation(n, 3)<