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A034904
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Related to sept-factorial numbers A045754.
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3
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1, 28, 980, 37730, 1531838, 64337196, 2766499428, 121034349975, 5365856182225, 240390356963680, 10861273400995360, 494187939745288880, 22618601857572837200, 1040455685448350511200, 48069052667713793617440
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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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
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MATHEMATICA
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CoefficientList[Series[(Power[1-49x, (-7)^-1]-1)/7, {x, 0, 30}], x] (* Harvey P. Dale, Aug 23 2011 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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