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A034325 a(n) = n-th quintic factorial number divided by 5. 11
1, 10, 150, 3000, 75000, 2250000, 78750000, 3150000000, 141750000000, 7087500000000, 389812500000000, 23388750000000000, 1520268750000000000, 106418812500000000000, 7981410937500000000000, 638512875000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..354

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 594

Norihiro Nakashima, Shuhei Tsujie, Enumeration of Flats of the Extended Catalan and Shi Arrangements with Species, arXiv:1904.09748 [math.CO], 2019.

FORMULA

5*a(n) = (5*n)(!^5) = Product_{j=1..n} 5*j = 5^(n-1)*n!.

E.g.f.: (-1 + (1-5*x)^(-1))/5, a(0) = 0.

D-finite with recurrence: a(n) -5*n*a(n-1)=0. - R. J. Mathar, Feb 24 2020

MAPLE

seq(5^(n-1)*n!, n=1..20); # G. C. Greubel, Aug 23 2019

MATHEMATICA

Array[5^(# - 1) #! &, 16] (* Michael De Vlieger, May 30 2019 *)

PROG

(PARI) vector(20, n, 5^(n-1)*n!) \\ G. C. Greubel, Aug 23 2019

(MAGMA) [5^(n-1)*Factorial(n): n in [1..20]]; // G. C. Greubel, Aug 23 2019

(Sage) [5^(n-1)*factorial(n) for n in (1..20)] # G. C. Greubel, Aug 23 2019

(GAP) List([1..20], n-> 5^(n-1)*Factorial(n) ); # G. C. Greubel, Aug 23 2019

CROSSREFS

Cf. A008548, A034300, A034301, A034323, A052562.

Sequence in context: A224124 A212472 A025750 * A335800 A239620 A253124

Adjacent sequences:  A034322 A034323 A034324 * A034326 A034327 A034328

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

STATUS

approved

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Last modified September 24 14:46 EDT 2021. Contains 347643 sequences. (Running on oeis4.)