A383577 a(n) = Sum_{k=0..floor(n/3)} binomial(n-k,k) * binomial(n-2*k,k)^2.
1, 1, 1, 3, 13, 37, 87, 241, 793, 2513, 7437, 22287, 70051, 222883, 700213, 2195139, 6959869, 22252933, 71201129, 227826699, 731309001, 2356460041, 7609531843, 24603325189, 79677148959, 258535824775, 840291483835, 2734637778217, 8910389207081, 29069537051081
Offset: 0
Keywords
Crossrefs
Cf. A383539.
Programs
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PARI
a(n) = sum(k=0, n\3, binomial(n-k, k)*binomial(n-2*k, k)^2);
Comments