|
Search: id:A121020
|
|
| |
|
| 1, 1, 7, 85, 1587, 41981, 1484643, 67306429, 3790883659, 258899180989, 21029065282803, 1999625128004813, 219691693064750283, 27580289062408474861, 3919060527556589637043, 625165018565884343909053
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
LINKS
|
N. J. A. Sloane, Transforms
|
|
FORMULA
|
a(n) = 1/(2*exp(1))*Sum_{r,s>=0} [r*s]^n/(2^r*s!), where [m]^n = m*(m+1)*...*(m+n-1) is the rising factorial.
|
|
MAPLE
|
read "transforms" ; A000670 := proc(n) local k ; if n = 0 then 1; else add(k!*combinat[stirling2](n, k), k=1..n) ; fi ; end: A000110 := proc(n) local k ; add(combinat[stirling2](n, k), k=0..n) ; end: A104600 := proc(n) local k ; add(combinat[stirling1](n, k)*A000670(k)*A000110(k), k=0..n) ; end: A121020 := proc(nmax) local a104600 ; a104600 := [seq(A104600(n), n=0..nmax)] ; LAH(a104600) ; end: A121020(20) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 21 2008
|
|
CROSSREFS
|
Sequence in context: A064089 A049412 A056547 this_sequence A000424 A060237 A000686
Adjacent sequences: A121017 A121018 A121019 this_sequence A121021 A121022 A121023
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 08 2006, Sep 19 2006
|
|
EXTENSIONS
|
More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 21 2008
|
|
|
Search completed in 0.002 seconds
|
