VOOZH about

URL: https://oeis.org/A021964

⇱ A021964 - OEIS

login
A021964
Expansion of g.f. 1/((1-x)*(1-4*x)*(1-9*x)*(1-11*x)).
1
1, 25, 422, 6050, 79563, 993675, 12002224, 141692500, 1645717205, 18887136125, 214818117306, 2426541462150, 27263857999327, 305049644712175, 3401871310224068, 37837512809631800, 419965002207076329, 4653386298894470625, 51491190851014824910, 569138573796247782250
OFFSET
0,2
FORMULA
a(n) = (12*11^(n+3) - 21*9^(n+3) + 4^(n+5) - 7)/1680. - Yahia Kahloune, Jun 26 2013
From Vincenzo Librandi, Jul 11 2013: (Start)
a(0)=1, a(1)=25, a(2)=422, a(3)=6050; for n>3, a(n) = 25*a(n-1) -203*a(n-2) +575*a(n-3) -396*a(n-4).
a(0)=1, a(1)=25; for n>1, a(n) = 20*a(n-1) -99*a(n-2) +(4^n - 1)/3. (End)
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 4 x) (1 - 9 x) (1 - 11 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 11 2013 *)
LinearRecurrence[{25, -203, 575, -396}, {1, 25, 422, 6050}, 20] (* Harvey P. Dale, Aug 24 2021 *)
PROG
(Magma) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-4*x)*(1-9*x)*(1-11*x)))); // Vincenzo Librandi, Jul 11 2013
(Magma) I:=[1, 25, 422, 6050]; [n le 4 select I[n] else 25*Self(n-1)-203*Self(n-2)+575*Self(n-3)-396*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Jul 11 2013
CROSSREFS
Sequence in context: A025953 A020595 A001456 * A022456 A020593 A025951
KEYWORD
nonn,easy
STATUS
approved