A252863 Number of Eulerian paths in a lattice graph bounded by the four equations x+y=1, x+y=2n, x-y=2, and x-y=-2.

1, 16, 304, 5824, 111616, 2139136, 40996864, 785711104, 15058272256, 288594067456, 5530948993024, 106001474781184, 2031534311735296, 38934662638206976, 746188703776374784, 14300819473316184064, 274077370205901684736, 5252734292544974749696

Offset

1,2

Links

Muhammad Kholilurrohman, Table of n, a(n) for n = 1..300

P. Audibert, Mathematics for Informatics and Computer Science, Wiley, 2010, p. 824.

Muhammad Kholilurrohman and Shin-ichi Minato, An Efficient Algorithm for Enumerating Eulerian Paths, Hokkaido University, Division of Computer Science, TCS Technical Reports, TCS-TR-A-14-77, Oct. 2014.

Formula

Empirical g.f.: (x - 4*x^2)/(1 - 20*x + 16*x^2) and recurrence a(n) = 20*a(n-1) - 16*a(n-2). - Robert Israel, Dec 26 2014

Crossrefs

Sequence in context: A300264 A253302 A227678 * A360431 A039746 A232834

Adjacent sequences: A252860 A252861 A252862 * A252864 A252865 A252866

Keyword

nonn

Author

Muhammad Kholilurrohman, Dec 23 2014

Status

approved