A174477 G.f.: exp( Sum_{n>=1} A174478(n)*x^n/n ) where A174478(n) = Sum_{d|n} d*2^(n/d)*tau(d).

1, 2, 8, 20, 58, 136, 348, 788, 1856, 4094, 9160, 19716, 42692, 90152, 190628, 396800, 825170, 1698432, 3490484, 7124396, 14517896, 29450384, 59654636, 120472948, 243010964, 489208250, 983952448, 1976442696, 3967448276, 7957317632

Offset

0,2

Comments

tau(n) = A000005(n) = the number of divisors of n.

Links

Table of n, a(n) for n=0..29.

Prog

(PARI) {a(n)=polcoeff(exp(sum(m=1, n, x^m/m*sumdiv(m, d, d*2^(m/d)*sigma(d, 0)))+x*O(x^n)), n)}

Crossrefs

Cf. A174478, A000005 (tau).

Sequence in context: A279898 A221066 A238760 * A024997 A081157 A099177

Adjacent sequences: A174474 A174475 A174476 * A174478 A174479 A174480

Keyword

nonn

Author

Paul D. Hanna, Apr 04 2010

Status

approved