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A021114
Expansion of 1/((1-x)(1-2x)(1-5x)(1-6x)).
1
1, 14, 131, 1036, 7497, 51450, 341167, 2209592, 14071013, 88494406, 551310123, 3409583268, 20966120449, 128339843282, 782754695399, 4760106416464, 28878529850205, 174860636120478, 1057111102343395
OFFSET
0,2
FORMULA
a(0)=1, a(1)=14; for n>1, a(n) = 11*a(n-1) -30*a(n-2) +2^n -1. - Vincenzo Librandi, Jul 07 2013
a(0)=1, a(1)=14, a(2)=131, a(3)=1036; for n>2, a(n) = 14*a(n-1) -65*a(n-2) +112*a(n-3) -60*a(n-4). - Vincenzo Librandi, Jul 07 2013
a(n) = (3*6^(n+3) - 5^(n+4) + 5*2^(n+3) - 3)/60. [Yahia Kahloune, Jul 07 2013]
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 2 x) (1 - 5 x) (1 - 6 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 07 2013 *)
LinearRecurrence[{14, -65, 112, -60}, {1, 14, 131, 1036}, 20] (* Harvey P. Dale, Dec 23 2023 *)
PROG
(Magma) I:=[1, 14, 131, 1036]; [n le 4 select I[n] else 14*Self(n-1)-65*Self(n-2)+112*Self(n-3)-60*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-2*x)*(1-5*x)*(1-6*x)))); // Vincenzo Librandi, Jul 07 2013
CROSSREFS
Sequence in context: A206207 A358168 A026936 * A328785 A375894 A113976
KEYWORD
nonn,easy
AUTHOR
STATUS
approved