A177570 Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, up, down, up

1, 6, 86, 2147, 86337, 5048158, 404763879, 42661639277, 5720539614420, 951006841725136

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Crossrefs

Sequence in context: A231165 A091881 A004701 * A343636 A369624 A047786

Adjacent sequences: A177567 A177568 A177569 * A177571 A177572 A177573

Keyword

nonn

Author

R. H. Hardin May 10 2010

Status

approved