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URL: https://oeis.org/A020593

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A020593
Expansion of g.f. 1/((1 - 6*x)*(1 - 8*x)*(1 - 11*x)).
1
1, 25, 423, 6053, 79079, 977613, 11662351, 135834661, 1556251287, 17625401981, 197992990559, 2211194243349, 24591484236775, 272666167778029, 3016684939110447, 33322861263616517, 367668910476901943, 4053314434522328157, 44658211693913532415, 491814961306132248565
OFFSET
0,2
FORMULA
a(n) = 18*6^n/5 -32*8^n/3 +121*11^n/15. - R. J. Mathar, Jun 30 2013
a(0)=1, a(1)=25, a(2)=423; for n>2, a(n) = 25*a(n-1) -202*a(n-2) +528*a(n-3). - Vincenzo Librandi, Jul 04 2013
a(n) = 19*a(n-1) -88*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013
E.g.f.: exp(6*x)*(54 - 160*exp(2*x) + 121*exp(5*x))/15. - Stefano Spezia, Mar 09 2026
MATHEMATICA
CoefficientList[Series[1 / ((1 - 6 x) (1 - 8 x) (1 - 11 x)), {x, 0, 20}], x] (* Vincenzo Librandi Jul 04 2013 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-8*x)*(1-11*x)))); // Vincenzo Librandi, Jul 04 2013
(Magma) I:=[1, 25, 423]; [n le 3 select I[n] else 25*Self(n-1) -202*Self(n-2)+528*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013
CROSSREFS
Sequence in context: A001456 A021964 A022456 * A025951 A021944 A299845
KEYWORD
nonn,easy
STATUS
approved