A048503 G.f.: (1 - 4*x + 6*x^2 - 2*x^3)/((1-x)^3*(1-2*x)^2).

1, 3, 8, 22, 61, 165, 430, 1080, 2627, 6223, 14428, 32874, 73849, 163977, 360602, 786604, 1704127, 3670227, 7864552, 16777470, 35651861, 75497773, 159383878, 335544672, 704643451, 1476395415, 3087008180, 6442451410

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• easy

Comments

a(n) = T(0,n) + T(1,n-1) + ... + T(n,0), array T given by A048494.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..2000
• Index entries for linear recurrences with constant coefficients, signature (7,-19,25,-16,4).

Programs

Magma

[(14+7*n+n^2+(n-3)*2^(n+2))/2 : n in [0..30]]; // Vincenzo Librandi, Sep 25 2011

Formula

a(n) = (14 + 7*n + n^2 + (n-3)*2^(n+2))/2. - T. D. Noe, Dec 11 2006

Extensions

Better definition from Ralf Stephan, Feb 05 2004

Corrected by T. D. Noe, Dec 11 2006