A073807 Number of divisors of sum of cube of divisors.

1, 3, 6, 2, 12, 18, 8, 12, 2, 20, 18, 12, 8, 24, 36, 4, 32, 6, 24, 24, 24, 30, 36, 72, 4, 24, 32, 16, 24, 60, 36, 16, 60, 48, 60, 4, 16, 72, 24, 80, 24, 72, 24, 36, 24, 60, 60, 24, 8, 12, 96, 16, 20, 96, 80, 96, 50, 40, 72, 72, 16, 108, 16, 8, 54, 100, 12, 64, 108, 100, 32, 24

Offset: 1

Author

Labos Elemer, Aug 13 2002

Keywords

• nonn

Comments

a(n) = 2 for n in A063783. - Robert Israel, Jul 12 2023

Examples

			For n=10: D={1,2,5,10}, 1+8+125+1000=1134, divisors(1134)={1,2,3,6,7,9,14,18,21,27,42,54,63,81,126,162,189,378,567,1134} so a(10)=20.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A001158, A062068, A063783, A073802-A073813.

Programs

Maple

f:= n -> numtheory:-tau(numtheory:-sigma[3](n)):
map(f, [$1..100]); # Robert Israel, Jul 12 2023

Mathematica

Table[DivisorSigma[0,DivisorSigma[3,n]],{n,80}] (* Harvey P. Dale, Dec 13 2011 *)

PARI

a(n) = numdiv(sigma(n, 3)); \\ Michel Marcus, Jul 13 2023

Formula

a(n) = A000005(A001158(n)).