cp's OEIS Frontend

A334455 a(n) is unique integer k such that sigma(A051281(n)) = tau(A051281(n))^k (where sigma is the sum of divisors (A000203) and tau the number of divisors (A000005)), with a(1) = 1.

%I A334455 #40 Nov 12 2020 01:16:36
%S A334455 1,2,3,5,7,4,5,4,6,13,5,8,17,6,9,19,10,10,7,11,11,8,8,12,12,13,9,9,7,
%T A334455 6,15,31,8,16,11,17,12,18,18,19,13,13,13,8,10,10,11,11,22,9,12,24,10,
%U A334455 25,17,17,13,13,14,14,14,19,12,12,15,15,61,21,16,32,13
%N A334455 a(n) is unique integer k such that sigma(A051281(n)) = tau(A051281(n))^k (where sigma is the sum of divisors (A000203) and tau the number of divisors (A000005)), with a(1) = 1.
%H A334455 Rémy Sigrist, <a href="/A334455/b334455.txt">Table of n, a(n) for n = 1..12885</a>
%H A334455 Rémy Sigrist, <a href="/A334455/a334455.png">Colored scatterplot of the first 12885 terms</a> (where the color is function of tau(A051281(n)))
%H A334455 Rémy Sigrist, <a href="/A334455/a334455.gp.txt">PARI program for A334455</a>
%F A334455 a(n) = log(A000203(A051281(n))) / log(A000005(A051281(n))) for n > 1.
%e A334455 For n = 7:
%e A334455 - A051281(7) = 889,
%e A334455 - sigma(889) = 1024,
%e A334455 - tau(889) = 4,
%e A334455 - 1024 = 4^5,
%e A334455 - so a(7) = 5.
%o A334455 (PARI) See Links section.
%Y A334455 Cf. A000005, A000203, A051281, A225369.
%K A334455 nonn
%O A334455 1,2
%A A334455 _Rémy Sigrist_, Nov 10 2020