A258389 a(n) = (n^(n+1)-(n-1)^n) + ((n+1)^n-n^(n-1)).

2, 14, 128, 1504, 21752, 374184, 7464368, 169402496, 4309519952, 121450640200, 3755499322808, 126409853754144, 4600799868451880, 180029930424249416, 7536568838736534752, 336087767194699956736, 15905186914751401828640, 796113699641442496367496

Offset: 1

Author

Daniel Suteu, May 28 2015

Keywords

• nonn

Examples

			For a(3) = (3^(3+1)-(3-1)^3) + ((3+1)^3-3^(3-1)) = (3^4 - 2^3) + (4^3 - 3^2) = 128.
		

Links

• Daniel Suteu, Table of n, a(n) for n = 1..20

Crossrefs

Cf. A051442, A084363, A178922.

Programs

Magma

[(n^(n+1)-(n-1)^n) + ((n+1)^n-n^(n-1)): n in [1..20]]; // Vincenzo Librandi, May 29 2015

Mathematica

Array[#^(# + 1) - (# - 1)^# + ((# + 1)^# - #^(# - 1)) &, 20] (* Vincenzo Librandi, May 29 2015 *)

Sidef

func a(n) {
     ((n+1)**n - n**(n-1)) -
     ((n-1)**n - n**(n+1))
};
1.to(Math.inf).each { |n|
    say a(n);
};

Formula

a(n) = (n^(n+1)-(n-1)^n) + ((n+1)^n-n^(n-1)) = A084363(n) + A178922(n).

a(n) = A051442(n) - A051442(n-1). - Mathew Englander, Jul 08 2020