OFFSET
0,2
COMMENTS
Binomial transform of A081187.
a(n) is also the number of words of length n over an alphabet of seven letters, of which a chosen one appears an even number of times. See a comment in A007582, also for the crossrefs. for the 1- to 11- letter word cases. - Wolfdieter Lang, Jul 17 2017
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Takao Komatsu, Some recurrence relations of poly-Cauchy numbers, J. Nonlinear Sci. Appl., (2019) Vol. 12, Issue 12, 829-845.
Index entries for linear recurrences with constant coefficients, signature (12,-35).
FORMULA
a(n) = 12*a(n-1) -35*a(n-2), a(0)=1, a(1)=6.
G.f.: (1-6*x)/((1-5*x)*(1-7*x)).
E.g.f.: exp(6*x)*cosh(x).
a(n) = 5^n/2 + 7^n/2.
MATHEMATICA
CoefficientList[Series[(1 - 6 x) / ((1 - 5 x) (1 - 7 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Aug 07 2013 *)
LinearRecurrence[{12, -35}, {1, 6}, 30] (* Harvey P. Dale, Mar 24 2016 *)
PROG
(Magma) [5^n/2+7^n/2: n in [0..25]]; // Vincenzo Librandi, Aug 07 2013
(PARI) a(n)=5^n/2+7^n/2 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Mar 11 2003
STATUS
approved