OFFSET
1,2
COMMENTS
LINKS
W. Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4.
FORMULA
a(n, m) = 5*(5*(n-1)+m)*a(n-1, m)/n + m*a(n-1, m-1)/n, n >= m >= 1; a(n, m) := 0, n<m; a(n, 0) := 0; a(1, 1)=1.
G.f. for m-th column: ((-1+(1-25*x)^(-1/5))/5)^m.
EXAMPLE
{1}; {15,1}; {275,30,1}; {5500,775,45,1}; ...
MATHEMATICA
a[n_, m_] := Coefficient[Series[((-1 + (1 - 25*x)^(-1/5))/5)^m, {x, 0, n}], x^n];
Flatten[Table[a[n, m], {n, 1, 9}, {m, 1, n}]][[1 ;; 38]]
(* Jean-François Alcover, Jun 21 2011, after g.f. *)
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved