A081301 Subdiagonal of square array A081297.

1, 1, 13, 41, 991, 5461, 194713, 1545265, 73022131, 758924981, 44709567013, 575279386969, 40614439994311, 623479972408021, 51316625644764721, 915589327332039905, 86090052046429522747, 1750836276286883890741

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, A081302.

Programs

Magma

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

Mathematica

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

Formula

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