OFFSET
0,2
COMMENTS
Binomial convolution of the Motzkin numbers.
FORMULA
a(n) ~ sqrt((76 + 5*(38*(247 - 27*sqrt(57)))^(1/3) + 5*(38*(247 + 27*sqrt(57)))^(1/3))/57)/4 * ((1261 + 57*sqrt(57))^(1/3)/6 + 56/(3*(1261 + 57*sqrt(57))^(1/3)) + 5/3)^n / sqrt(Pi*n). - Vaclav Kotesovec, May 24 2021
Conjecture D-finite with recurrence -4*(3035*n-11997) *(2*n+1) *(n+1) *a(n) +2*(153546*n^3-490325*n^2-62942*n+71982) *a(n-1) +2*(-452090*n^3+1745622*n^2-1405285*n-226200) *a(n-2) -2 *(n-2)*(83741*n^2-200458*n-19650) *a(n-3) -3*(n-2) *(n-3) *(46423*n+6938) *a(n-4)=0. - R. J. Mathar, Nov 02 2021
MAPLE
a := n -> add(binomial(n, k)^2 * hypergeom([(k-n)/2, (k-n+1)/2], [k+2], 4), k = 0..n); seq(simplify(a(n)), n = 0..24);
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, May 23 2021
STATUS
approved