OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..500
A. Straub, V. H. Moll, and T. Amdeberhan, The p-adic valuation of k-central binomial coefficients, Acta Arith. 140 (1) (2009) 31-41, eq (1.10)
FORMULA
G.f.: (1-81*x)^(-1/9).
D-finite with recurrence: n*a(n) = 9*(9*n-8)*a(n-1). - R. J. Mathar, Jan 28 2020
a(n) = 9^(2*n) * Pochhammer(n, 1/9)/n!. - G. C. Greubel, Oct 19 2022
MATHEMATICA
CoefficientList[Series[1/Surd[1-81x, 9], {x, 0, 20}], x] (* Harvey P. Dale, Mar 08 2018 *)
Table[9^(2*n)*Pochhammer[1/9, n]/n!, {n, 0, 40}] (* G. C. Greubel, Oct 19 2022 *)
PROG
(Magma) [n le 1 select 1 else 9*(9*n-17)*Self(n-1)/(n-1): n in [1..40]]; // G. C. Greubel, Oct 19 2022
(SageMath) [9^(2*n)*rising_factorial(1/9, n)/factorial(n) for n in range(40)] # G. C. Greubel, Oct 19 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved