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A074619
a(n) = 6^n + 7^n.
7
2, 13, 85, 559, 3697, 24583, 164305, 1103479, 7444417, 50431303, 342941425, 2340123799, 16018069537, 109949704423, 756587236945, 5217746494519, 36054040477057, 249557173431943, 1729973554578865, 12008254925383639
OFFSET
0,1
FORMULA
G.f.: 1/(1-6*x)+1/(1-7*x). E.g.f.: e^(6*x)+e^(7*x). - Mohammad K. Azarian, Jan 11 2009
a(n)=13*a(n-1)-42*a(n-2) with a(0)=2, a(1)=13. - Vincenzo Librandi, Jul 21 2010
MATHEMATICA
Table[6^n + 7^n, {n, 0, 20}]
CoefficientList[Series[1/(1 - 6*x) + 1/(1 - 7*x), {x, 0, 20}], x] (* Vincenzo Librandi, Jan 11 2013 *)
LinearRecurrence[{13, -42}, {2, 13}, 30] (* Harvey P. Dale, Mar 30 2019 *)
PROG
(Magma) [7^n+6^n: n in [0..20]]; // Vincenzo Librandi, Jan 11 2013
(PARI) a(n)=6^n+7^n \\ Charles R Greathouse IV, Oct 07 2015
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 26 2002
STATUS
approved