A084860 Expansion of (1 - 2x + 2x^2 - x^3)/(1 - 2x)^2.
1, 2, 6, 15, 36, 84, 192, 432, 960, 2112, 4608, 9984, 21504, 46080, 98304, 208896, 442368, 933888, 1966080, 4128768, 8650752, 18087936, 37748736, 78643200, 163577856, 339738624, 704643072, 1459617792, 3019898880, 6241124352
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (4,-4).
Programs
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Mathematica
CoefficientList[Series[(1-2x+2x^2-x^3)/(1-2x)^2,{x,0,50}],x] (* Harvey P. Dale, Mar 30 2011 *)
Formula
a(0)=1, a(n+1) = 3*2^(n-2)*(n+3) - 0^n/4.
Equals binomial transform of nonzero terms of A026741: (1, 1, 3, 2, 5, 3, 7, 4, ...). - Gary W. Adamson, Apr 25 2008
Equals row sums of triangle A139633. - Gary W. Adamson, Apr 27 2008
Comments