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A081628
a(n) = 2*(-1)^n - (-5)^n.
1
1, 3, -23, 123, -623, 3123, -15623, 78123, -390623, 1953123, -9765623, 48828123, -244140623, 1220703123, -6103515623, 30517578123, -152587890623, 762939453123, -3814697265623, 19073486328123, -95367431640623, 476837158203123, -2384185791015623, 11920928955078123
OFFSET
0,2
COMMENTS
Inverse binomial transform of A081629.
FORMULA
G.f.: (1+9*x)/((1+x)*(1+5*x)).
E.g.f.: 2*exp(-x) - exp(-5*x).
a(n) = A033999(n)*(2 - A000351(n)). - Elmo R. Oliveira, Dec 05 2023
MATHEMATICA
CoefficientList[Series[(1 + 9 x) / ((1 + x) (1 + 5 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Aug 09 2013 *)
LinearRecurrence[{-6, -5}, {1, 3}, 30] (* Harvey P. Dale, Jan 08 2021 *)
PROG
(Magma) [2*(-1)^n-(-5)^n: n in [0..25]]; // Vincenzo Librandi, Aug 09 2013
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 26 2003
STATUS
approved