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A034904 Related to sept-factorial numbers A045754. 3
1, 28, 980, 37730, 1531838, 64337196, 2766499428, 121034349975, 5365856182225, 240390356963680, 10861273400995360, 494187939745288880, 22618601857572837200, 1040455685448350511200, 48069052667713793617440 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Convolution of A034835(n-1) with A025752(n), n >= 1.
LINKS
Elżbieta Liszewska, Wojciech Młotkowski, Some relatives of the Catalan sequence, arXiv:1907.10725 [math.CO], 2019.
FORMULA
a(n) = 7^(n-1)*A045754(n)/n!, A045754(n)=(7*n-6)(!^7) := product(7*j-6, j=1..n); G.f. (-1+(1-49*x)^(-1/7))/7.
D-finite with recurrence: n*a(n) +7*(-7*n+6)*a(n-1)=0. - R. J. Mathar, Jan 28 2020
MATHEMATICA
CoefficientList[Series[(Power[1-49x, (-7)^-1]-1)/7, {x, 0, 30}], x] (* Harvey P. Dale, Aug 23 2011 *)
CROSSREFS
Sequence in context: A203135 A097579 A091549 * A189995 A228689 A218480
KEYWORD
easy,nonn
AUTHOR
STATUS
approved

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Last modified July 21 02:16 EDT 2024. Contains 374462 sequences. (Running on oeis4.)