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A034724 a(n) = n-th sextic factorial number divided by 4. 11
1, 10, 160, 3520, 98560, 3351040, 134041600, 6165913600, 320627507200, 18596395417600, 1190169306726400, 83311851470848000, 6331700711784448000, 519199458366324736000, 45689552336236576768000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..345

FORMULA

4*a(n) = (6*n-2)(!^6) = Product_{j=1..n} (6*j-2).

a(n) = 2^(n+1)*A034000(n), 2*A034000(n) = (3*n-1)(!^3).

E.g.f.: (-1 + (1-6*x)^(-2/3))/4.

MAPLE

seq( mul(6*j-2, j=1..n)/4, n=1..20); # G. C. Greubel, Nov 11 2019

MATHEMATICA

With[{nn=20}, CoefficientList[Series[((1-6x)^(-2/3)-1)/4, {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jun 02 2017 *)

Table[6^n*Pochhammer[2/3, n]/4, {n, 20}] (* G. C. Greubel, Nov 11 2019 *)

PROG

(PARI) vector(20, n, prod(j=1, n, 6*j-2)/4 ) \\ G. C. Greubel, Nov 11 2019

(MAGMA) [(&*[6*j-2: j in [1..n]])/4: n in [1..20]]; // G. C. Greubel, Nov 11 2019

(Sage) [product( (6*j-2) for j in (1..n))/4 for n in (1..20)] # G. C. Greubel, Nov 11 2019

(GAP) List([1..20], n-> Product([1..n], j-> 6*j-2)/4 ); # G. C. Greubel, Nov 11 2019

CROSSREFS

Cf. A034000, A008542, A034689.

Sequence in context: A106261 A112125 A090374 * A234283 A074703 A190903

Adjacent sequences:  A034721 A034722 A034723 * A034725 A034726 A034727

KEYWORD

easy,nonn,changed

AUTHOR

Wolfdieter Lang

STATUS

approved

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Last modified November 13 04:20 EST 2019. Contains 329085 sequences. (Running on oeis4.)