A024951 a(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=a(2)=1 and a(3)=5.

1, 1, 5, 5, 5, 30, 55, 80, 230, 530, 1080, 2505, 5555, 15130, 34705, 80530, 197855, 511455, 1249430, 2966155, 7334380, 18923630, 46926130, 114708755, 287150005, 741017280, 1860971930, 4628582080, 11629943105, 30291303280, 76640090080, 192409197255

Offset

1,3

Links

Table of n, a(n) for n=1..32.

Mathematica

a = {1, 1, 5}; n = 4; Do[ a = Append[a, Sum[a[[2 i - 1]]*a[[n - 2 i + 1]], {i, 1, Floor[(n + 2)/4]}]]; n++, 29]; a  (* Jake L Lande, Jul 03 2024 *)

Crossrefs

Sequence in context: A262122 A216876 A019162 * A092519 A198585 A224093

Adjacent sequences: A024948 A024949 A024950 * A024952 A024953 A024954

Keyword

nonn

Author

Clark Kimberling

Extensions

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

Status

approved