A081298 Main diagonal of the square array A081297.

1, 1, 7, 25, 461, 2821, 84883, 734161, 30684601, 342800821, 18348174791, 251203133545, 16394732478853, 265727053328101, 20464206411678331, 383172119935376161, 34011762638354230001, 722380674949394645269

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. A081299, A081300, A081301, A081302.

Programs

Magma

[((n+1)^(n+1)-(-n)^(n+1))/(2*n+1): n in [0..20]]; // Vincenzo Librandi, Aug 07 2013

Mathematica

Table[((n + 1)^(n + 1) - (-n)^(n + 1)) / (2 n + 1),{n, 0, 20}] (* Vincenzo Librandi, Aug 07 2013 *)

Formula

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