A034255 - OEIS

A034255

Related to quartic factorial numbers A007696.

1, 10, 120, 1560, 21216, 297024, 4243200, 61526400, 902387200, 13355330560, 199115837440, 2986737561600, 45030812467200, 681895160217600, 10364806435307520, 158063298138439680, 2417438677411430400

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OFFSET

1,2

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..833

W. Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4.

Elżbieta Liszewska, Wojciech Młotkowski, Some relatives of the Catalan sequence, arXiv:1907.10725 [math.CO], 2019.

FORMULA

a(n) = 4^(n-1)*A007696(n)/n!, A007696(n)=(4*n-3)(!^4) := product(4*j-3, j=1..n), n >= 1; G.f. (-1+(1-16*x)^(-1/4))/4.

Convolution of A034385(n-1) with A025749(n), n >= 1.

D-finite with recurrence: n*a(n) +4*(-4*n+3)*a(n-1)=0. - R. J. Mathar, Jan 28 2020

MATHEMATICA

Rest[CoefficientList[Series[(-1+(1-16x)^(-1/4))/4, {x, 0, 20}], x]] (* Harvey P. Dale, May 19 2011 *)

CROSSREFS

Cf. A007696. a(n)= A048882(n, 1) (first column of triangle).

Sequence in context: A318495 A320760 A366711 * A363310 A051582 A122420

Adjacent sequences: A034252 A034253 A034254 * A034256 A034257 A034258

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

STATUS

approved