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A191678
Number of lattice paths from (0,0) to (n,n) using steps (1,0), (1,1), (0,2), (2,2).
0
1, 1, 5, 15, 62, 233, 937, 3729, 15121, 61492, 251942, 1036215, 4279754, 17731181, 73670725, 306823695, 1280574706, 5354602495, 22426876445, 94070238840, 395106054632, 1661489413472, 6994494531010, 29474635716345, 124319047552309, 524797934104312, 2217091297558466, 9373180869094923
OFFSET
0,3
FORMULA
G.f.: A(x) where (4*x^6+12*x^5-20*x^3+27*x^2+12*x-4)*A(x)^3-(3*x^2+3*x-3)*A(x)+1 = 0. - Mark van Hoeij, Apr 17 2013
MAPLE
P := (4*x^6+12*x^5-20*x^3+27*x^2+12*x-4)*A^3-(3*x^2+3*x-3)*A+1;
Q := eval(P, A=A+1):
series(RootOf(Q, A)+1, x=0, 30); # Mark van Hoeij, Apr 17 2013
PROG
(PARI) /* same as in A092566 but use */
steps=[[1, 0], [1, 1], [0, 2], [2, 2]];
/* Joerg Arndt, Jun 30 2011 */
KEYWORD
nonn
AUTHOR
Joerg Arndt, Jun 30 2011
STATUS
approved