A024961 a(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=2, a(2)=1, and a(3)=3.

2, 1, 3, 6, 12, 33, 84, 204, 507, 1410, 3828, 10185, 27048, 78720, 222051, 613770, 1704360, 4978050, 14312460, 40615440, 115306545, 341021994, 994082808, 2865120612, 8271370236, 24556630128, 72215184450, 210645965832, 614238371328, 1836536385786

Offset

1,1

Links

Table of n, a(n) for n=1..30.

Crossrefs

Sequence in context: A095024 A049900 A024741 * A260666 A140644 A321651

Adjacent sequences: A024958 A024959 A024960 * A024962 A024963 A024964

Keyword

nonn

Author

Clark Kimberling

Extensions

Offset corrected and title improved by Sean A. Irvine, Jul 30 2019

Status

approved