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A030039
a(n+1) = Sum_{k=0..floor(4*n/5)} a(k) * a(n-k).
4
1, 1, 1, 2, 4, 9, 21, 42, 97, 233, 570, 1414, 3319, 8208, 20595, 52370, 133955, 328261, 833652, 2136155, 5519116, 14341917, 36069212, 93074465, 241613666, 630653714, 1652472131, 4215072482, 10985970447, 28756470626, 75580683613, 199201407564, 513021407584
OFFSET
0,4
LINKS
PROG
(PARI) lista(nn) = {my(v=vector(nn+2, i, 1)); for(n=1, nn, v[n+2]=sum(k=1, 1+(4*n)\5, v[k]*v[n+2-k])); v; } \\ Jinyuan Wang, Mar 18 2020
CROSSREFS
KEYWORD
nonn
EXTENSIONS
More terms from Jinyuan Wang, Mar 18 2020
STATUS
approved