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A280756
Expansion of (1 + 2*x)/(1 - x - 4*x^2 + x^4).
1
1, 3, 7, 19, 46, 119, 296, 753, 1891, 4784, 12052, 30435, 76752, 193708, 488664, 1233061, 3110965, 7849501, 19804697, 49969640, 126077463, 318106522, 802611677, 2025068125, 5109437370, 12891603348, 32526741151, 82068086418, 207065613652, 522446355976, 1318182069433, 3325899406919
OFFSET
0,2
LINKS
R. Sachdeva and A. K. Agarwal, Combinatorics of certain restricted n-color composition functions, Discrete Mathematics, 340, (2017), 361-372. See sequence C_5.
MATHEMATICA
CoefficientList[Series[(1+2x)/(1-x-4x^2+x^4), {x, 0, 40}], x] (* or *) LinearRecurrence[ {1, 4, 0, -1}, {1, 3, 7, 19}, 40] (* Harvey P. Dale, Jun 23 2022 *)
CROSSREFS
Sequence in context: A348008 A185696 A141344 * A029855 A209397 A377003
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jan 16 2017
STATUS
approved