A048121 a(n) = (1/2)*T(2n,n+1), where T is given by A048113.

0, 0, 1, 3, 12, 42, 156, 570, 2124, 7926, 29844, 112812, 428712, 1635108, 6259236, 24031260, 92517180, 357019224, 1380671532, 5349496152, 20762603724, 80709201504, 314178212928, 1224576411084, 4778651920092, 18667769062044

Offset

1,4

Links

Table of n, a(n) for n=1..26.

Crossrefs

Cf. A048113.

Sequence in context: A067819 A094970 A065179 * A191112 A066987 A366617

Adjacent sequences: A048118 A048119 A048120 * A048122 A048123 A048124

Keyword

nonn

Author

Clark Kimberling

Status

approved