A027330 a(n) = Sum_{k=0..m} T(n,k) * T(n,k+1), where m=0 for n=1; m=n+1 for n >= 2; and T is given by A026148.

1, 6, 50, 394, 3120, 24922, 200676, 1627434, 13282008, 109014050, 899304906, 7452793766, 62019712684, 518052932358, 4342182907626, 36509428285466, 307859922637008, 2602876165613074, 22060637925756358, 187399432888840254, 1595268339755117256

Offset

1,2

Links

Table of n, a(n) for n=1..21.

Crossrefs

Sequence in context: A180880 A308860 A318162 * A090409 A212233 A180910

Adjacent sequences: A027327 A027328 A027329 * A027331 A027332 A027333

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 27 2019

Status

approved