A090879 a(n) = Sum_{d|n} d*2^(n-d).

1, 4, 7, 20, 21, 94, 71, 328, 457, 1194, 1035, 7052, 4109, 17294, 33807, 83984, 65553, 389650, 262163, 1484820, 1949717, 4216854, 4194327, 29409304, 22020121, 67215386, 119799835, 350453788, 268435485, 1755807774, 1073741855

Offset

1,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..3000

Formula

G.f.: Sum_{m>0} m*x^m/(1-(2*x)^m).

Mathematica

f[n_] := Block[{d = Divisors[n]}, Apply[Plus, d*2^(n - d)]]; Table[ f[n], {n, 1, 32}] (* Robert G. Wilson v, Feb 16 2004 *)

Crossrefs

Cf. A074854, A083413.

Sequence in context: A127415 A045548 A359733 * A084404 A147065 A049947

Adjacent sequences: A090876 A090877 A090878 * A090880 A090881 A090882

Keyword

easy,nonn

Author

Vladeta Jovovic, Feb 14 2004

Extensions

More terms from Robert G. Wilson v, Feb 16 2004

Status

approved