OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
G.f.: 1/((1-12*x)*sqrt(1-12*x)).
a(n) = Jacobi_P(n,1/2,1/2,1)*12^n.
a(n) = 3^n*(2*n+1)*binomial(2*n,n) = 3^n*A002457(n).
a(n) = (2*n+1)*A098658(n).
D-finite with recurrence: n*a(n) - 6*(2*n+1)*a(n-1) = 0. - R. J. Mathar, Nov 07 2012
From Amiram Eldar, Jan 27 2024: (Start)
Sum_{n>=0} 1/a(n) = 12*arcsin(1/sqrt(12))/sqrt(11).
Sum_{n>=0} (-1)^n/a(n) = 12*arcsinh(1/sqrt(12))/sqrt(13). (End)
MATHEMATICA
CoefficientList[Series[(1-12x)^(-3/2), {x, 0, 20}], x] (* Harvey P. Dale, Oct 26 2016 *)
PROG
(Magma) [(3^n*Factorial(2*n)/Factorial(n)^2)*(2*n+1): n in [0..20]]; // Vincenzo Librandi, Jul 05 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Feb 02 2006
STATUS
approved