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A021374
Expansion of 1/((1-x)(1-3x)(1-4x)(1-8x)).
1
1, 16, 173, 1604, 13833, 115032, 938821, 7588108, 61024865, 489508448, 3921394269, 31392726612, 251228899897, 2010181938664, 16082865641717, 128668587186716, 1029371410275729, 8235062327044080, 65880863376836365
OFFSET
0,2
FORMULA
a(0)=1, a(1)=16; for n>1, a(n) = 12*a(n-1) -32*a(n-2) +(3^n-1)/2. - Vincenzo Librandi, Jul 09 2013
a(0)=1, a(1)=16, a(2)=173, a(3)=1604; for n>3, a(n) = 16*a(n-1) -83*a(n-2) +164*a(n-3) -96*a(n-4). - Vincenzo Librandi, Jul 09 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 3 x) (1 - 4 x) (1 - 8 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 09 2013 *)
PROG
(Magma) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-3*x)*(1-4*x)*(1-8*x)))); /* or */ I:=[1, 16, 173, 1604]; [n le 4 select I[n] else 16*Self(n-1)-83*Self(n-2)+164*Self(n-3)-96*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Jul 09 2013
CROSSREFS
Sequence in context: A221789 A018209 A021174 * A253343 A215687 A187720
KEYWORD
nonn,easy
AUTHOR
STATUS
approved