A260775 Certain directed lattice paths.

1, 4, 28, 264, 2860, 33592, 416024, 5348880, 70715340, 955277400, 13128240840, 182965127280, 2579808294648, 36734706144304, 527495903500720, 7629973004184608, 111068129754096396, 1625888084299461528, 23919596771720906984, 353467725574013402800

Offset: 0

Author

N. J. A. Sloane, Jul 30 2015

Keywords

• nonn
• easy

Comments

See Dziemianczuk (2014) for precise definition.

Links

• Lars Blomberg, Table of n, a(n) for n = 0..100
• M. Dziemianczuk, On Directed Lattice Paths With Additional Vertical Steps, arXiv preprint arXiv:1410.5747 [math.CO], 2014.
• Maciej Dziemiańczuk, On directed lattice paths with vertical steps, Discrete Math., 339 (2016), 1116-1139.
• Alex Hall, OEIS explorer

Crossrefs

Cf. A000108, A260769, A260770, A260771, A260772, A260773, A260774, A260776.

Formula

See Dziemianczuk (2014) Equation (36b) with N=2.

a(n) = 2 * A000108(2*n) for n > 0. [Agrees with the reference, found using OEIS explorer.] - Andrey Zabolotskiy, May 08 2021

Extensions

More terms from Lars Blomberg, Aug 01 2015