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A021254
Expansion of 1/((1-x)(1-2x)(1-7x)(1-12x)).
1
1, 22, 341, 4646, 59661, 743358, 9112405, 110693878, 1337742173, 16118816558, 193887174117, 2329875721446, 27981116089837, 335931645121822, 4032287505801077, 48395204420052950, 580796733493846653
OFFSET
0,2
FORMULA
a(n) = (3*12^(n+3) - 11*7^(n+3) + 33*2^(n+3) - 25)/1650. [Yahia Kahloune, Jul 07 2013]
a(0)=1, a(1)=22, a(2)=341, a(3)=4646; for n>3, a(n) = 22*a(n-1) -143*a(n-2) +290*a(n-3) -168*a(n-4). - Vincenzo Librandi, Jul 08 2013
a(0)=1, a(1)=22; for n>1, a(n) = 19*a(n-1) -84*a(n-2) +2^n -1. - Vincenzo Librandi, Jul 08 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 2 x) (1 - 7 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 08 2013 *)
LinearRecurrence[{22, -143, 290, -168}, {1, 22, 341, 4646}, 30] (* Harvey P. Dale, Jul 22 2013 *)
PROG
(Magma) I:=[1, 22, 341, 4646]; [n le 4 select I[n] else 22*Self(n-1)-143*Self(n-2)+290*Self(n-3)-168*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-2*x)*(1-7*x)*(1-12*x)))); // Vincenzo Librandi, Jul 08 2013
CROSSREFS
Sequence in context: A018070 A332873 A019490 * A231647 A083449 A272525
KEYWORD
nonn,easy
AUTHOR
STATUS
approved