OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..345
FORMULA
6*a(n) = (6*n)(!^6) = Product_{j=1..n} 6*j = 6^n*n!.
E.g.f.: (-1 + 1/(1-6*x))/6.
D-finite with recurrence: a(n) - 6*n*a(n-1) = 0. - R. J. Mathar, Feb 24 2020
From Amiram Eldar, Jan 08 2022: (Start)
Sum_{n>=1} 1/a(n) = 6*(exp(1/6)-1).
Sum_{n>=1} (-1)^(n+1)/a(n) = 6*(1-exp(-1/6)). (End)
MAPLE
seq(6^(n-1)*n!, n=1..20); # G. C. Greubel, Nov 11 2019
MATHEMATICA
Table[6^(n-1)*n!, {n, 20}] (* Harvey P. Dale, Dec 22 2013 *)
PROG
(PARI) vector(20, n, 6^(n-1)*n!) \\ G. C. Greubel, Nov 11 2019
(Magma) [6^(n-1)*Factorial(n): n in [1..20]]; // G. C. Greubel, Nov 11 2019
(Sage) [6^(n-1)*factorial(n) for n in (1..20)] # G. C. Greubel, Nov 11 2019
(GAP) List([1..20], n-> 6^(n-1)*Factorial(n) ); # G. C. Greubel, Nov 11 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved