A061765 a(n) = usigma(sigma(n)), where usigma(n) is the sum of unitary divisors of n (A034448) and sigma(n) is the sum of the divisors (A000203).

1, 4, 5, 8, 12, 20, 9, 24, 14, 30, 20, 40, 24, 36, 36, 32, 30, 56, 30, 96, 33, 50, 36, 120, 32, 96, 54, 72, 72, 90, 33, 80, 68, 84, 68, 112, 60, 120, 72, 180, 96, 132, 60, 160, 168, 90, 68, 160, 80, 128, 90, 150, 84, 216, 90, 216, 102, 180, 120, 288

Offset

1,2

Links

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

Formula

a(n) = A034448(A000203(n)). - Amiram Eldar, Aug 26 2022

Mathematica

a[n_] := Times @@ (1 + Power @@@ FactorInteger[DivisorSigma[1, n]]); a[1] = 1; Array[a, 100] (* Amiram Eldar, Aug 26 2022 *)

Crossrefs

Cf. A000203, A034448.

Sequence in context: A011980 A260163 A362560 * A242274 A297419 A230549

Adjacent sequences: A061762 A061763 A061764 * A061766 A061767 A061768

Keyword

nonn

Author

N. J. A. Sloane, Oct 30 2001

Status

approved