

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).


28



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]


CROSSREFS

Sequence in context: A291290 A006047 A285712 * A328219 A130542 A128502
Adjacent sequences: A062065 A062066 A062067 * A062069 A062070 A062071


KEYWORD

nonn


AUTHOR

Amarnath Murthy, Jun 13 2001


EXTENSIONS

Corrected and extended by Jason Earls, Jun 16 2001


STATUS

approved



