A030041 - OEIS

%I #7 Mar 18 2020 05:02:46

%S 1,1,2,3,5,12,23,45,92,183,434,936,2012,4365,9551,20748,45065,108070,

%T 245109,553308,1253492,2846553,6482338,14721344,33423804,75916943,

%U 187505118,441004027,1032009219,2419549459,5676752449,13331861333,31398821908,73794930935

%N a(n+1) = Sum_{k=0..sqrt(n)} a(k) * a(n-k).

%o (PARI) lista(nn) = {my(v=vector(nn+2, i, 1)); for(n=0, nn, v[n+2]=sum(k=1, 1+sqrt(n), v[k]*v[n+2-k])); v; } \\ _Jinyuan Wang_, Mar 18 2020

%Y Cf. A000992.

%K nonn

%O 0,3

%A _N. J. A. Sloane_

%E More terms from _Jinyuan Wang_, Mar 18 2020