A083306 a(n) = (4*(n+15)^n + n^n)/5.

1, 13, 232, 4671, 104308, 2560625, 68622228, 1995651019, 62652143668, 2113523516277, 76295945312500, 2936332651924343, 120077491457688948, 5201749713019676569, 238048808542004682388, 11479213178778076171875, 581942186746562952973108, 30948666430186884139830941

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Formula

a(n) ~ (4*exp(15-225/(2*n))+1) * n^n / 5. - Amiram Eldar, Feb 09 2026

Mathematica

Unprotect[Power]; Power[0, 0]=1; Protect[Power]; a[n_]:=(4*(n+15)^n + n^n)/5; Array[a, 16, 0] (* Stefano Spezia, Sep 19 2025 *)

Prog

(Magma) [(4*(n+15)^n+n^n)/5: n in [0..25]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)= (4*(n+15)^n+n^n)/5 \\ Charles R Greathouse IV, Jun 29 2011

Crossrefs

Cf. A000312, A083304, A083305.

Sequence in context: A388916 A083081 A388049 * A114755 A142610 A218202

Adjacent sequences: A083303 A083304 A083305 * A083307 A083308 A083309

Keyword

easy,nonn

Author

Paul Barry, Apr 24 2003

Status

approved