OFFSET
0,3
FORMULA
a(n) = (-1)^n * Sum_{k=0..n} (-2)^k * binomial(n,k) * binomial(3*k+1,n) / (3*k+1).
D-finite with recurrence n*(2*n+1)*a(n) +3*(-11*n^2+14*n-4)*a(n-1) +27*(5*n-7) *(n-2)*a(n-2) -27*(7*n-16)*(n-3)*a(n-3) +81*(n-3)*(n-4)*a(n-4)=0. - R. J. Mathar, Jul 25 2023
MAPLE
A364437 := proc(n)
(-1)^n*add((-2)^k* binomial(n, k) * binomial(3*k+1, n) / (3*k+1), k=0..n) ;
end proc:
seq(A364437(n), n=0..70); # R. J. Mathar, Jul 25 2023
PROG
(PARI) a(n) = (-1)^n*sum(k=0, n, (-2)^k*binomial(n, k)*binomial(3*k+1, n)/(3*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 24 2023
STATUS
approved