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A136045 Bisection of A138546. 0
1, 4, 42, 660, 12810, 281736, 6727644, 170316432, 4504487130, 123255492360, 3465702008340, 99645553785960, 2918768920720380, 86852063374902000, 2619552500788984200, 79939673971478231760 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..15.

FORMULA

G.f.: ((41472*x^3 - 11520*x^2 + 288*x)*g'' + (-23040*x + 432 + 103680*x^2)*g' + (20736*x-864)*g)/1728 where g is the o.g.f. of A002896. - Mark van Hoeij, Nov 12 2011

a(n) = hypergeom([1/2,-n,-n],[1,2],4)*binomial(2*n,n). - Mark van Hoeij, May 13 2013

MAPLE

sq := (1-40*x+144*x^2)^(1/2); pb := 54*x*(108*x^2-27*x+1+(9*x-1)*sq);

H1 := hypergeom([7/6, 1/3], [1], pb); H2 := hypergeom([1/6, 4/3], [1], pb);

fa := (10-72*x-6*sq)^(1/2)/(216*x);

ogf := fa*((648*x^2+90*x+1+(54*x+3)*sq)*H1^2 - (612*x-7+3*sq)*H1*H2 + 8*(72*x-1)*H2^2); series(ogf, x=0, 20); # Mark van Hoeij, Nov 12 2011

CROSSREFS

Sequence in context: A153854 A216080 A137645 * A192949 A156453 A327200

Adjacent sequences:  A136042 A136043 A136044 * A136046 A136047 A136048

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 25 2008

STATUS

approved

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Last modified September 24 06:24 EDT 2020. Contains 337317 sequences. (Running on oeis4.)