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A140313
First differences of A140298.
1
1, 0, 0, 1, 1, 1, 1, 4, 4, 1, 13, 13, 1, 40, 40, 1, 121, 121, 1, 364, 364, 1, 1093, 1093, 1, 3280, 3280, 1, 9841, 9841, 1, 29524, 29524, 1, 88573, 88573, 1, 265720, 265720, 1, 797161, 797161, 1, 2391484, 2391484, 1, 7174453, 7174453, 1, 21523360, 21523360, 1, 64570081
OFFSET
0,8
LINKS
FORMULA
Mix 1, A003462(n), A003462(n).
G.f.: (x - 1)*(x^3 + 3*x^2 + 2*x + 1)/((3*x^3 - 1)*(x^2 + x + 1)). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 12 2009
MATHEMATICA
CoefficientList[Series[(x - 1) (x^3 + 3 x^2 + 2 x + 1)/((3 x^3 - 1) (x^2 + x + 1)), {x, 0, 52}], x] (* Michael De Vlieger, Nov 05 2018 *)
PROG
(PARI) Vec((1 - x)*(1 + 2*x + 3*x^2 + x^3)/((1 - 3*x^3)*(1 + x + x^2)) + O(x^40)) \\ Andrew Howroyd, Nov 03 2018
(Magma) m:=50; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!( (x-1)*(x^3+3*x^2+2*x+1)/((3*x^3-1)*(x^2+x+1)) )); // G. C. Greubel, Nov 21 2018
(Sage) s=((x-1)*(x^3+3*x^2+2*x+1)/((3*x^3-1)*(x^2+x+1))).series(x, 50);
s.coefficients(x, sparse=False) # G. C. Greubel, Nov 21 2018
CROSSREFS
Sequence in context: A365674 A106026 A096078 * A102323 A145902 A124028
KEYWORD
nonn
AUTHOR
Paul Curtz, May 25 2008
EXTENSIONS
Terms a(33) and beyond from Andrew Howroyd, Nov 03 2018
STATUS
approved