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A021772
Expansion of 1/((1-x)(1-4x)(1-5x)(1-9x)).
1
1, 19, 242, 2618, 26103, 248997, 2316784, 21251956, 193359485, 1751044295, 15814841406, 142616378814, 1284983809747, 11572125768313, 104185847231708, 937857633325592, 8441649467754489, 75979521955403451
OFFSET
0,2
FORMULA
a(0)=1, a(1)=19, a(2)=242, a(3)=2618, a(n)=19*a(n-1)-119*a(n-2)+ 281*a(n-3)- 180*a(n-4). [Harvey P. Dale, Jul 23 2011]
a(n) = (3*9^(n+3)-30*5^(n+3)+32*4^(n+3)-5)/480. - Yahia Kahloune, May 23 2013.
MATHEMATICA
CoefficientList[Series[1/((1-x)(1-4x)(1-5x)(1-9x)), {x, 0, 40}], x] (* or *) LinearRecurrence[{19, -119, 281, -180}, {1, 19, 242, 2618}, 41] (* Harvey P. Dale, Jul 23 2011 *)
CROSSREFS
Sequence in context: A025933 A107203 A021544 * A019783 A021504 A019512
KEYWORD
nonn,easy
AUTHOR
STATUS
approved