

A090879


a(n) = Sum_{dn} d*2^(nd).


1



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



OFFSET

1,2


LINKS

Table of n, a(n) for n=1..31.


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: A275389 A127415 A045548 * 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



