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A049375 A convolution triangle of numbers obtained from A034687. 4
1, 15, 1, 275, 30, 1, 5500, 775, 45, 1, 115500, 19250, 1500, 60, 1, 2502500, 471625, 44625, 2450, 75, 1, 55412500, 11495000, 1254000, 85000, 3625, 90, 1, 1246781250, 279675000, 34093125, 2698875, 143750, 5025, 105, 1, 28398906250, 6802812500 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n,1) = A034687(n). a(n,m)=: s2(6; n,m), a member of a sequence of unsigned triangles including s2(2; n,m)= A007318(n-1,m-1) (Pascal's triangle). s2(3; n,m)= A035324(n,m), s2(4; n,m)= A035529(n,m), s2(5; n,m)= A048882(n,m).
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
Cf. A039746.
Sequence in context: A049327 A030527 A027467 * A049224 A223517 A027448
KEYWORD
easy,nonn,tabl
AUTHOR
STATUS
approved

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Last modified February 24 16:16 EST 2024. Contains 370307 sequences. (Running on oeis4.)