A048504 a(n) = T(n,n), array T given by A048494.

1, 2, 7, 28, 101, 326, 967, 2696, 7177, 18442, 46091, 112652, 270349, 638990, 1490959, 3440656, 7864337, 17825810, 40108051, 89653268, 199229461, 440401942, 968884247, 2122317848, 4630511641

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..2000
• Index entries for linear recurrences with constant coefficients, signature (8, -25, 38, -28, 8).

Programs

Magma

[n*(n-1)*2^(n-1) + n + 1 : n in [0..30]]; // Vincenzo Librandi, Sep 25 2011

Mathematica

Table[n(n-1)2^(n-1)+n+1,{n,0,30}] (* or *) LinearRecurrence[{8,-25,38,-28,8},{1,2,7,28,101},30] (* Harvey P. Dale, Jul 29 2021 *)

Formula

a(n) = n*(n-1)*2^(n-1) + n + 1. - Ralf Stephan, Jan 15 2004

G.f.: (-1 - 4*x^4 + 16*x^3 - 16*x^2 + 6*x)/((x-1)^2*(2*x-1)^3). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 13 2009