|
| |
|
|
A121886
|
|
a(n) = (1/n!)* Sum_{k=0..n} |Stirling1(n,k)|*A122399(k).
|
|
0
| |
|
|
1, 1, 5, 40, 444, 6324, 110023, 2261576, 53632424, 1441341350, 43290170494, 1437020742408, 52243864528990, 2064488610832106, 88106523694973953, 4038627301344466648, 197888243609535940091, 10321811633042512528240
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| Number of square matrices with nonnegative integer entries and without zero rows such that sum of all entries is equal to n. - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 04 2008
|
|
|
FORMULA
| G.f.: Sum_{n>=0} ( 1/(1-x)^n - 1 )^n.
|
|
|
EXAMPLE
| G.f.: A(x) = 1 + x + 5*x^2 + 40*x^3 + 444*x^4 + 6324*x^5 +...
where
A(x) = 1 + (1/(1-x) - 1) + (1/(1-x)^2 - 1)^2 + (1/(1-x)^3 - 1)^3 +...
|
|
|
PROG
| (PARI) {a(n)=polcoeff(sum(m=0, n, (1/(1-x+x*O(x^n))^m-1)^m), n)}
|
|
|
CROSSREFS
| Cf. A104209.
Sequence in context: A202477 A034000 A000359 * A052868 A094574 A090362
Adjacent sequences: A121883 A121884 A121885 * A121887 A121888 A121889
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 31 2006
|
|
|
EXTENSIONS
| More terms from Max Alekseyev (maxale(AT)gmail.com), Feb 01 2007
|
| |
|
|
