A259926 a(n) = n^(2*n) - n^(2*n - 1).

0, 8, 486, 49152, 7812500, 1813985280, 581334062442, 246290604621824, 133417453597332552, 90000000000000000000, 74002499442581601012110, 72872109936441607122321408, 84676920178401799992368876316, 114656931713301654695784797437952, 178967655284025147557258605957031250

Offset: 1

Author

Ilya Gutkovskiy, Jul 09 2015

Keywords

• nonn

Crossrefs

Cf. A005408, A005843, A062206, A085524, A086815.

Programs

Magma

[n^(2*n) - n^(2*n - 1): n in [1..20]]; // Vincenzo Librandi, Jul 10 2015

Mathematica

Table[n^(2 n) - n^(2 n - 1), {n, 15}]
Array[#^(2 #) - #^(2 # - 1)&, 15] (* Vincenzo Librandi, Jul 10 2015 *)

PARI

vector(20, n, n^(2*n) - n^(2*n-1)) \\ Michel Marcus, Jul 09 2015

Sage

[n**(2*n) - n**(2*n - 1) for n in range(1, 20)] # Anders Hellström, Jul 10 2015

Formula

a(n) = A062206(n) - A085524(n).

a(n) = n^A005843(n) - n^A005408(n-1).

a(n) = n! * [x^n] LambertW(-n*x)^2 / (1 + LambertW(-n*x)). - Ilya Gutkovskiy, Mar 24 2020