A048496 a(n) = 2^(n-1)*(3*n-4) + 3.

1, 2, 7, 23, 67, 179, 451, 1091, 2563, 5891, 13315, 29699, 65539, 143363, 311299, 671747, 1441795, 3080195, 6553603, 13893635, 29360131, 61865987, 130023427, 272629763, 570425347, 1191182339, 2483027971, 5167382531

Offset: 0

Author

Clark Kimberling

Keywords

• nonn
• easy

Comments

a(n) = T(2, n), 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 (5, -8, 4).

Crossrefs

n-th difference of a(n), a(n-1), ..., a(0) is (1, 4, 7, 10, ...).

Programs

Magma

[2^(n-1)*(3*n-4)+3 : n in [0..30]]; // Vincenzo Librandi, Sep 26 2011

Formula

a(n) = A027992(n-1) + 1 = A053565(n) + 3.

From R. J. Mathar, Oct 31 2008: (Start)

a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3).

G.f.: (1 - 3*x + 5*x^2)/((1-x)(1-2*x)^2). (End)

Extensions

Formula from Ralf Stephan, Jan 15 2004