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A235389
Number of paths joining opposite corners of an n X n grid with every vertex appearing at most twice in the path.
0
22, 9482, 112269228, 37515056726494, 355023905438833546724
OFFSET
2,1
EXAMPLE
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
Sequence in context: A200460 A202054 A279298 * A267491 A013727 A370314
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
a(5)-a(6) from Muhammad Kholilurrohman, Nov 13 2014
STATUS
approved