|
| |
|
|
A159666
|
|
a(0)=1. For n >= 1, a(n) = sum{k=1 to n} binomial(n,k) * GCD(n,k) * a(k-1).
|
|
1
| |
|
|
1, 1, 4, 18, 104, 665, 5430, 45647, 457008, 4903380, 58782190, 735362309, 10577094600, 153445432699, 2462688382448, 41517435884340, 752130797186176, 13961847566945787, 284698729314200574, 5855054339061479491
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| a(n) is divisible by n, for all n >= 1.
|
|
|
MATHEMATICA
| f[n_] := f[n] = Sum[Binomial[n, k] GCD[n, k] f[k - 1], {k, n}]; f[0] = 1; Table[f@n, {n, 0, 20}] [From Robert G. Wilson v (rgwv(AT)rgwv.com), May 27 2009]
|
|
|
CROSSREFS
| A159667
Sequence in context: A201826 A064852 A191365 * A051827 A007711 A020114
Adjacent sequences: A159663 A159664 A159665 * A159667 A159668 A159669
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Leroy Quet, Apr 19 2009
|
|
|
EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), May 27 2009
|
| |
|
|
