A326038 Square root of the largest square dividing the sum of divisors of n: a(n) = A000188(sigma(n)).

1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 2, 2, 1, 2, 2, 1, 3, 1, 2, 1, 4, 6, 2, 2, 1, 1, 2, 2, 1, 6, 4, 3, 4, 3, 4, 1, 1, 2, 2, 3, 1, 4, 2, 2, 1, 6, 4, 2, 1, 1, 6, 7, 3, 2, 6, 2, 4, 3, 2, 2, 1, 4, 2, 1, 2, 12, 2, 3, 4, 12, 6, 1, 1, 1, 2, 2, 4, 2, 4, 1, 11, 3, 2, 4, 6, 2, 2, 6, 3, 3, 4, 2, 8, 12, 2, 6, 7, 3, 2, 1, 1, 6, 2, 1, 8

Offset: 1

Author

Antti Karttunen, Jun 05 2019

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000188, A000196, A326038, A326039, A326040.

Programs

Mathematica

Table[Last[Select[Sqrt[#]&/@Divisors[DivisorSigma[1,n]],IntegerQ]],{n,120}] (* Harvey P. Dale, Jun 25 2022 *)

PARI

A000188(n) = core(n, 1)[2]; \\ From A000188
A326038(n) = A000188(sigma(n));

Formula

a(n) = A000188(A000203(n)) = A000196(A326039(n)).