A105863 a(n) = n * Sum_{d|n} (binomial(n,d) / gcd(n,d)).

1, 6, 12, 44, 30, 252, 56, 856, 846, 3080, 132, 20616, 182, 49532, 52110, 237232, 306, 1227096, 380, 4106320, 2470272, 15525092, 552, 86092176, 1328900, 270424752, 126624006, 1157002616, 870, 5577100260, 992, 19572325728, 6386892930

Offset: 1

Author

Robert G. Wilson v, Apr 23 2005

Keywords

• nonn

Crossrefs

Cf. A056045, A105861, A105862.

Programs

Mathematica

f[n_] := Block[{d = Divisors[n]}, n*Plus @@ (Binomial[n, d])]; Table[ f[n], {n, 34}]

Formula

a(n) = n * A056045(n) = n * Sum_{d|n} (binomial(n, d) / gcd(n, d)).