A081302 Subdiagonal of square array A081297.

1, 1, 21, 61, 1891, 9633, 404713, 2997541, 159902271, 1564345201, 101406750589, 1236882490845, 94479649710811, 1382731226210881, 121677107761110993, 2079381120597925237, 207197254527662127511, 4051708966720224576081

Offset: 0

Author

Paul Barry, Mar 17 2003

Keywords

• easy
• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

Cf. A081298, A081299, A081300, A081301.

Programs

Magma

[((n+3)^(n+1)-(-(n+2))^(n+1))/(2*n+5): n in [0..20]]; // Vincenzo Librandi, Aug 08 2013

Mathematica

Table[((n + 3)^(n + 1) - (-(n + 2))^(n + 1)) / (2 n + 5), {n, 0, 20}] (* Vincenzo Librandi, Aug 08 2013 *)

Formula

a(n) = ((n+3)^(n+1)-(-(n+2))^(n+1))/(2*n+5).