|
| |
|
|
A009277
|
|
E.g.f. exp(tanh(x)^2) (even powers only).
|
|
0
| |
|
|
1, 2, -4, -88, 4496, -155488, 675776, 903834752, -178181918464, 26154843525632, -2632795710260224, -207121926659381248, 274561534481040183296, -132684091405061956722688, 50873850498309673207709696
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
FORMULA
| a(n)=sum(m=1..n, sum(k=0..2*n-2*m, binomial(k+2*m-1,2*m-1)*(k+2*m)!*(-1)^(k)*2^(2*n-2*m-k)*stirling2(2*n,k+2*m))/m!); [From Vladimir Kruchinin, Jun 06 2011]
|
|
|
MATHEMATICA
| Exp[ Tanh[ x ]^2 ] (* Even Part *)
|
|
|
PROG
| (Maxima)
a(n):=sum(sum(binomial(k+2*m-1, 2*m-1)*(k+2*m)!*(-1)^(k)*2^(2*n-2*m-k)*stirling2(2*n, k+2*m), k, 0, 2*n-2*m)/m!, m, 1, n); [From Vladimir Kruchinin, Jun 06 2011]
|
|
|
CROSSREFS
| Sequence in context: A015170 A013146 A116310 * A018410 A156496 A007534
Adjacent sequences: A009274 A009275 A009276 * A009278 A009279 A009280
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| R. H. Hardin (rhhardin(AT)att.net)
|
|
|
EXTENSIONS
| Extended with signs Mar 15 1997 by Olivier Gerard.
|
| |
|
|
