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A021144 Expansion of 1/((1-x)(1-2x)(1-5x)(1-10x)). 1
1, 18, 227, 2520, 26481, 271278, 2745247, 27615060, 276964061, 2773708938, 27757433067, 277676053200, 2777269152841, 27775234648998, 277765062125687, 2777714199500940, 27777459886360821, 277776188320627458 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(0)=1, a(1)=18, a(2)=227, a(3)=2520; for n>2, a(n) = 18*a(n-1) -97*a(n-2) +180*a(n-3) -100*a(n-4). - Vincenzo Librandi, Jul 07 2013
a(0)=1, a(1)=18; for n>1, a(n) = 15*a(n-1)-50*a(n-2) +2^n -1. - Vincenzo Librandi, Jul 07 2013
a(n) = (10^(n+3) - 6*5^(n+3) + 15*2^(n+3) - 10)/360. [Yahia Kahloune, Jul 07 2013]
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 2 x) (1 - 5 x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 07 2013 *)
LinearRecurrence[{18, -97, 180, -100}, {1, 18, 227, 2520}, 30] (* Harvey P. Dale, Aug 24 2015 *)
PROG
(Magma) I:=[1, 18, 227, 2520]; [n le 4 select I[n] else 18*Self(n-1)-97*Self(n-2)+180*Self(n-3)-100*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)*(1-10*x)))); // Vincenzo Librandi, Jul 07 2013
CROSSREFS
Sequence in context: A017933 A021384 A056950 * A296854 A296941 A016312
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)