A081299 Diagonal of square array A081297.

1, 3, 13, 181, 1281, 32551, 314245, 11638089, 141943681, 6914792611, 101829922701, 6152865979261, 106138316846017, 7657555132292703, 151395000617362741, 12699162274678909201, 283052059672669084161

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, A081300, A081301, A081302.

Programs

Magma

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

Mathematica

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

Formula

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