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A249997 Expansion of 1/((1-x)*(1+3*x)*(1-4*x)). 3
1, 2, 15, 40, 221, 702, 3355, 11780, 52041, 193402, 817895, 3138720, 12953461, 50618102, 206059635, 813476860, 3286192481, 13047914802, 52482224575, 209057202200, 838843897101, 3347530323502, 13413657088715, 53584020970740, 214547906035321, 857556157684202 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
G.f.: 1/((1-x) * (1+3*x) * (1-4*x)).
a(n) = (-1)^n*3^(n+2)/28 + 4^(n+2)/21 -1/12. - R. J. Mathar, Jan 09 2015
E.g.f.: (1/84)*(27*exp(-3*x) - 7*exp(x) + 64*exp(4*x)). - G. C. Greubel, Jul 21 2022
MATHEMATICA
LinearRecurrence[{2, 11, -12}, {1, 2, 15}, 50] (* G. C. Greubel, Jul 21 2022 *)
PROG
(Magma) [((-1)^n*3^(n+3) +4^(n+3) -7)/84: n in [0..50]]; // G. C. Greubel, Jul 21 2022
(SageMath) [((-1)^n*3^(n+3) +4^(n+3) -7)/84 for n in (0..50)] # G. C. Greubel, Jul 21 2022
CROSSREFS
Sequence in context: A070170 A033568 A200156 * A032016 A254856 A001007
KEYWORD
nonn,easy
AUTHOR
Alex Ratushnyak, Dec 28 2014
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)