A235389 Number of paths joining opposite corners of an n X n grid with every vertex appearing at most twice in the path.

22, 9482, 112269228, 37515056726494, 355023905438833546724

Offset: 2

Author

Muhammad Kholilurrohman, Jan 09 2014

Keywords

• nonn
• more

Examples

			The 22 paths in a 2 X 2 grid whose nodes are numbered from 1 to 4 in the natural way are 124, 134, 12124, 12134, 12424, 12434, 13124, 13134, 13424, 13434, 1212434, 1213424, 1213434, 1242134, 1243124, 1243134, 1312424, 1312434, 1313424, 1342124, 1342134, 1343124. - _Giovanni Resta_, Mar 24 2014
		

Crossrefs

Cf. A007764, A239688.

Extensions

a(5)-a(6) from Muhammad Kholilurrohman, Nov 13 2014