A074225 a(n) = n * Sum_{d|n} d*2^(d-1).

1, 10, 39, 148, 405, 1254, 3143, 8488, 20853, 52050, 123915, 297804, 692237, 1611974, 3687795, 8405584, 18939921, 42512562, 94634003, 209819940, 462431697, 1015269486, 2218786839, 4832458392, 10485762025, 22684180610, 48922424415, 105229923596

Offset: 1

Author

N. J. A. Sloane, Jun 15 2003

Keywords

• nonn

Links

• Colin Barker, Table of n, a(n) for n = 1..1000
• N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, arXiv:math/0307064 [math.CO], 2003.
• N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, Order 21 (2004), 83-89.

Crossrefs

Equals n*A083413(n).

Programs

Mathematica

a[n_] := n*DivisorSum[n, #*2^(#-1)&]; Array[a, 30] (* Jean-François Alcover, Dec 03 2015 *)

PARI

vector(100, n, n*sumdiv(n, d, d*2^(d-1))) \\ Colin Barker, Jan 29 2015