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A026841
a(n) = T(2n,n-4), T given by A026725.
3
1, 11, 79, 471, 2535, 12809, 62067, 292085, 1345718, 6102780, 27343148, 121359692, 534632836, 2341151646, 10201950700, 44278673806, 191540714294, 826265471868, 3555992623850, 15273547250820, 65491352071266, 280412963707416
OFFSET
4,2
COMMENTS
Column k=10 of triangle A236830. - Philippe Deléham, Feb 02 2014
LINKS
FORMULA
a(n) = A026848(n). - Philippe Deléham, Feb 02 2014
G.f.: (x^4*C(x)^10)/(1-x*C(x)^3) where C(x) is the g.f. of A000108. - Philippe Deléham, Feb 02 2014
MATHEMATICA
Drop[CoefficientList[Series[(1-Sqrt[1-4*x])^10/(128*x^4*(8*x^2 -(1 - Sqrt[1-4*x])^3 )), {x, 0, 40}], x], 4] (* G. C. Greubel, Jul 17 2019 *)
PROG
(PARI) my(x='x+O('x^40)); Vec((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1 - sqrt(1-4*x))^3 ))) \\ G. C. Greubel, Jul 17 2019
(Magma) R<x>:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( (1-Sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-Sqrt(1-4*x))^3 )) )); // G. C. Greubel, Jul 17 2019
(Sage) a=((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-sqrt(1-4*x))^3 ))).series(x, 45).coefficients(x, sparse=False); a[4:40] # G. C. Greubel, Jul 17 2019
CROSSREFS
Cf. A236830.
Sequence in context: A139953 A111067 A172067 * A026848 A026864 A243416
KEYWORD
nonn
STATUS
approved