A026987 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026681.

1, 6, 35, 154, 613, 2882, 14995, 68730, 291606, 1378110, 7047087, 32801046, 143237183, 681449778, 3462931356, 16261134650, 72210836920, 345094694354, 1747534150303, 8253521588404, 37063741964059, 177681801860358, 897584067273979, 4256535683245074, 19269823577105032

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Crossrefs

Sequence in context: A078799 A203288 A026957 * A030532 A333800 A026997

Adjacent sequences: A026984 A026985 A026986 * A026988 A026989 A026990

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 20 2019

Status

approved