A027120 a(n) = A027113(n, 2n-2).

2, 7, 20, 56, 155, 429, 1188, 3298, 9181, 25634, 71781, 201569, 567538, 1601971, 4532460, 12851882, 36516613, 103955432, 296471643, 846932919, 2423256440, 6943726380, 19924638557, 57247669927, 164688166948, 474323305547

Offset

2,1

Links

Table of n, a(n) for n=2..27.

Crossrefs

Cf. A027113.

Sequence in context: A000149 A080041 A049681 * A094982 A292400 A007460

Adjacent sequences: A027117 A027118 A027119 * A027121 A027122 A027123

Keyword

nonn

Author

Clark Kimberling

Status

approved