A332224 a(n) = A087808(sigma(n)).

1, 2, 4, 3, 4, 8, 8, 4, 5, 10, 8, 12, 6, 16, 16, 5, 10, 7, 12, 14, 32, 20, 16, 16, 5, 14, 24, 24, 8, 40, 32, 6, 32, 12, 32, 10, 12, 16, 24, 18, 14, 64, 16, 28, 14, 40, 32, 20, 13, 11, 40, 34, 12, 32, 40, 32, 48, 18, 16, 56, 10, 64, 40, 7, 28, 80, 36, 12, 64, 80, 40, 34, 22, 26, 20, 40, 64, 56, 48, 22, 17, 12, 28, 96, 24, 68, 32, 36, 18

Offset: 1

Author

Antti Karttunen, Feb 12 2020

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16383
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A087808, A332225.

Cf. also A324293.

Programs

Mathematica

Block[{s = DivisorSigma[1, Range[90]], t}, t = Nest[Append[#1, If[EvenQ[#2], 2 #1[[#2/2 + 1]], #1[[(#2 - 1)/2 + 1]] + 1]] & @@ {#, Length@ #} &, {0}, Max@ s]; t[[Most@ s + 1]] ] (* Michael De Vlieger, Feb 12 2020 *)

PARI

A087808(n) = if(n<1, 0, if(n%2==0, 2*A087808(n/2), A087808((n-1)/2)+1));
A332224(n) = A087808(sigma(n));

Formula

a(n) = A087808(A000203(n)).