A155612 7^n - 3^n + 1.

1, 5, 41, 317, 2321, 16565, 116921, 821357, 5758241, 40333925, 282416201, 1977149597, 13840755761, 96887416085, 678218289881, 4747547161037, 33232887522881, 232630384847045, 1628413210489961, 11398894023111677

Offset: 0

Author

Mohammad K. Azarian, Jan 26 2009

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (11,-31,21).

Crossrefs

Cf. A155596, A155597, A155598, A155599, A155600, A155601, A155602, A155603, A155604, A155605, A155606, A155607, A155608, A155609, A155610, A155611.

Programs

PARI

a(n)=7^n-3^n+1 \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: 1/(1-7*x)-1/(1-3*x)+1/(1-x).

E.g.f.: e^(7*x)-e^(3*x)+e^x.

a(n) = 10*a(n-1)-21*a(n-2)+12 with a(0)=1, a(1)=5. - Vincenzo Librandi, Jul 21 2010