A062068 - OEIS

A062068

a(n) = d(sigma(n)), where d(k) is the number of divisors function (A000005) and sigma(k) is the sum of divisor function (A000203).

1, 2, 3, 2, 4, 6, 4, 4, 2, 6, 6, 6, 4, 8, 8, 2, 6, 4, 6, 8, 6, 9, 8, 12, 2, 8, 8, 8, 8, 12, 6, 6, 10, 8, 10, 4, 4, 12, 8, 12, 8, 12, 6, 12, 8, 12, 10, 6, 4, 4, 12, 6, 8, 16, 12, 16, 10, 12, 12, 16, 4, 12, 8, 2, 12, 15, 6, 12, 12, 15, 12, 8, 4, 8, 6, 12, 12, 16, 10, 8, 3, 12, 12, 12, 12, 12

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

EXAMPLE

d(sigma(5)) = d(6) = 4.

MATHEMATICA

Table[DivisorSigma[0, DivisorSigma[1, n]], {n, 1, 80}] (* Carl Najafi, Aug 16 2011 *)

PROG

(PARI) for(n=1, 120, print(numdiv(sigma(n))))

(PARI) { for (n=1, 1000, write("b062068.txt", n, " ", numdiv(sigma(n))) ) } \\ Harry J. Smith, Jul 31 2009