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A034830 a(n) = n-th sept-factorial number divided by 3. 9
1, 10, 170, 4080, 126480, 4806240, 216280800, 11246601600, 663549494400, 43794266630400, 3196981464019200, 255758517121536000, 22250990989573632000, 2091593153019921408000, 211250908455012062208000, 22815098113141302718464000, 2623736283011249812623360000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..339

Index entries for sequences related to factorial numbers

FORMULA

3*a(n) = (7*n-4)(!^7) = Product_{j=1..n} (7*j-4).

E.g.f.: (-1 + (1-7*x)^(-3/7))/3.

MATHEMATICA

Drop[With[{nn = 40}, CoefficientList[Series[(-1 + (1 - 7*x)^(-3/7))/3, {x, 0, nn}], x]*Range[0, nn]!], 1] (* G. C. Greubel, Feb 23 2018 *)

PROG

(PARI) x='x+O('x^30); Vec(serlaplace((-1 + (1-7*x)^(-3/7))/3)) \\ G. C. Greubel, Feb 23 2018

CROSSREFS

Cf. A045754, A034829, A034831, A034832, A034833, A034834.

Sequence in context: A325911 A246501 A120977 * A098345 A119043 A187204

Adjacent sequences:  A034827 A034828 A034829 * A034831 A034832 A034833

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

EXTENSIONS

More terms added by G. C. Greubel, Feb 23 2018

STATUS

approved

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Last modified October 16 13:51 EDT 2019. Contains 328093 sequences. (Running on oeis4.)