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A035278 One ninth of deca-factorial numbers. 11
1, 19, 551, 21489, 1052961, 62124699, 4286604231, 338641734249, 30139114348161, 2983772320467939, 325231182931005351, 38702510768789636769, 4992623889173863143201, 693974720595166976904939, 103402233368679879558835911, 16440955105620100849854909849 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
9*a(n) = (10*n-1)(!^10) = Product_{j=1..n} (10*j-1).
E.g.f.: (-1+(1-10*x)^(-9/10))/9.
a(n) = (Pochhammer(9/10,n) * 10^n)/9.
Sum_{n>=1} 1/a(n) = 9*(e/10)^(1/10)*(Gamma(9/10) - Gamma(9/10, 1/10)). - Amiram Eldar, Dec 22 2022
MAPLE
seq( mul(10*j-1, j=1..n)/9, n=1..20); # G. C. Greubel, Nov 11 2019
MATHEMATICA
Table[10^n*Pochhammer[9/10, n]/9, {n, 20}] (* G. C. Greubel, Nov 11 2019 *)
PROG
(PARI) vector(20, n, prod(j=1, n, 10*j-1)/9 ) \\ G. C. Greubel, Nov 11 2019
(Magma) [(&*[10*j-1: j in [1..n]])/9: n in [1..20]]; // G. C. Greubel, Nov 11 2019
(Sage) [product( (10*j-1) for j in (1..n))/9 for n in (1..20)] # G. C. Greubel, Nov 11 2019
(GAP) List([1..20], n-> Product([1..n], j-> 10*j-1)/9 ); # G. C. Greubel, Nov 11 2019
CROSSREFS
Sequence in context: A309313 A158211 A278184 * A092611 A008990 A012845
KEYWORD
easy,nonn
AUTHOR
STATUS
approved

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Last modified July 17 18:09 EDT 2024. Contains 374377 sequences. (Running on oeis4.)