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A024719
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a(n) = (1/3)*(2 + sum of C(3k,k)) for k = 0,1,2,...,n.
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0
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1, 2, 7, 35, 200, 1201, 7389, 46149, 291306, 1853581, 11868586, 76380826, 493606726, 3201081874, 20821158234, 135776966762, 887393271311, 5811082966886, 38119865826421, 250447855600321, 1647729357535486
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n)=sum{k=0..n, C(k-n,2n-2k)}. [From Paul Barry (pbarry(AT)wit.ie), Mar 15 2010]
G.f.: (1-2*g)/((3*g-1)*(g^3-2*g^2+g-1)) where g*(1-g)^2 = x. - Mark van Hoeij, Nov 09 2011
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MAPLE
| a:=n->(sum((binomial(-j, -3*j)), j=0..n)): seq(a(n), n=0..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 03 2007
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CROSSREFS
| Sequence in context: A057298 A058941 A020066 * A086637 A172511 A130458
Adjacent sequences: A024716 A024717 A024718 * A024720 A024721 A024722
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KEYWORD
| nonn
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 01 2000
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