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A020573
Expansion of 1/((1-6x)(1-7x)(1-11x)).
1
1, 24, 391, 5406, 68497, 824460, 9612667, 109824522, 1238345653, 13843811256, 153896453503, 1704525493398, 18833608743769, 207769555090212, 2289742482517699, 25217579128356834, 277609074266467645
OFFSET
0,2
FORMULA
a(n) = 36*6^n/5 -49*7^n/4 +121*11^n/20. - R. J. Mathar, Jun 30 2013
a(0)=1, a(1)=24, a(2)=391; for n>2, a(n) = 24*a(n-1) -185*a(n-2) +462*a(n-3). - Vincenzo Librandi, Jul 04 2013
a(n) = 18*a(n-1) -77*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 6 x) (1 - 7 x) (1 - 11 x)), {x, 0, 20}], x] (* Harvey P. Dale, Mar 24 2011 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-7*x)*(1-11*x)))); /* or */ I:=[1, 24, 391]; [n le 3 select I[n] else 24*Self(n-1)-185*Self(n-2)+462*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013
CROSSREFS
Sequence in context: A025970 A021924 A020494 * A022448 A025947 A007752
KEYWORD
nonn,easy
AUTHOR
STATUS
approved