A342284 Number of friendly 3-watermelons of length n.

1, 0, 2, 6, 24, 110, 550, 2922, 16242, 93520, 553980, 3359384, 20777588, 130696662, 834244830, 5393850898, 35272830054, 233016356788, 1553427829684, 10441803227652, 70715551631992, 482201548554776, 3308810614160224, 22836540660981088, 158458108961055864

Offset: 0

Author

N. J. A. Sloane, Mar 19 2021

Keywords

• nonn

References

• Essam, J.W. and Guttmann, A.J., 1995. Vicious walkers and directed polymer networks in general dimensions. Physical Review E, 52(6), pp. 5849ff. See (63).
• Iwan Jensen, Three friendly walkers, Journal of Physics A: Mathematical and Theoretical, Volume 50:2 (2017), #24003, 14 pages; https://doi.org/10.1088/1751-8121/50/2/024003. See F_3(x).

Crossrefs

Cf. A001181, A342282.

Formula

G.f. = 1 - 2*x + G(x), where G(x) = 2*x+2*x^2+6*x^3+24*x^4+110*x^5+550*x^6+... is the g.f. for A342282.