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

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A027113.