A027141 a(n) = Sum_{k=0..2n-1} T(n,k) * T(n,k+1), with T given by A027113.

3, 23, 165, 1218, 9247, 71688, 564759, 4506005, 36324407, 295341956, 2418783687, 19932773439, 165151576215, 1374850036253, 11493442158373, 96443092570534, 811995039077311, 6857352935798972, 58071096513853991, 493014496906492215, 4195315394988567303

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Extensions

More terms from Sean A. Irvine, Oct 23 2019