Column 2 of triangle A098539, which shifts left one column under the matrix square.

A098541

Column 2 of triangle A098539, which shifts left one column under the matrix square.

Terms

    a(0) =1a(1) =4a(2) =20a(3) =140a(4) =1460a(5) =23884a(6) =639156a(7) =28895052a(8) =2260707508a(9) =311748794188

External references