A121213 a(n) = 7^n - 5^n.
0, 2, 24, 218, 1776, 13682, 102024, 745418, 5374176, 38400482, 272709624, 1928498618, 13597146576, 95668307282, 672119557224, 4717043931818, 33080342678976, 231867574534082, 1624598900644824, 11379821699045018
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (12,-35).
Programs
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Mathematica
Table[7^n-5^n,{n,0,20}] (* or *) LinearRecurrence[{12,-35},{0,2},20] (* Harvey P. Dale, Feb 10 2018 *) -
PARI
a(n)=7^n-5^n \\ Charles R Greathouse IV, Oct 07 2015
Formula
a(n) = 12*a(n-1) - 35*a(n-2) with a(0)=0, a(1)=2. - Vincenzo Librandi, Jul 21 2010
a(n) = 2*A081200(n). - Reinhard Zumkeller, Aug 01 2010
G.f.: 2*x/((5*x-1)*(7*x-1)). - Colin Barker, Nov 05 2012
E.g.f.: 2*exp(6*x)*sinh(x). - Elmo R. Oliveira, Mar 31 2025