A030032 - OEIS

%I #11 Oct 15 2021 08:02:13

%S 1,1,1,1,2,3,5,10,18,33,66,127,244,506,1009,2018,4229,8631,17631,

%T 37265,77349,160433,342807,720334,1513791,3254445,6902283,14634519,

%U 31602375,67522598,144182089,312851626,672411931,1444776938,3145883976,6794243911,14667444523

%N a(n+1) = Sum_{k=0..floor(n/3)} a(k) * a(n-k).

%H Seiichi Manyama, <a href="/A030032/b030032.txt">Table of n, a(n) for n = 0..1000</a>

%o (PARI) lista(nn) = {my(v=vector(nn+2, i, 1)); for(n=3, nn, v[n+2]=sum(k=1, 1+n\3, v[k]*v[n+2-k])); v; } \\ _Jinyuan Wang_, Mar 18 2020

%Y Cf. A000992, A030034, A030036.

%K nonn

%O 0,5

%A _N. J. A. Sloane_

%E More terms from _Jinyuan Wang_, Mar 18 2020