OFFSET
0,3
FORMULA
a(0) = 1; a(n) = (-1)^n * a(n-1) + 2 * Sum_{k=0..n-1} a(k) * a(n-k-1).
MAPLE
A349011 := proc(n)
option remember ;
if n = 0 then
1;
else
(-1)^n*procname(n-1)+2*add(procname(k)*procname(n-k-1), k=0..n-1) ;
end if;
end proc:
seq(A349011(n), n=0..40) ; # R. J. Mathar, Aug 19 2022
MATHEMATICA
nmax = 24; A[_] = 0; Do[A[x_] = (1 - x A[-x])/(1 - 2 x A[x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
a[0] = 1; a[n_] := a[n] = (-1)^n a[n - 1] + 2 Sum[a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 24}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 05 2021
STATUS
approved