A162111 Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in strictly increasing order, and no more than 3 ones in any row or column.

2, 4, 9, 47, 243, 1498, 9764, 69794, 532844, 4401981, 38603493, 360697300, 3556444163, 36962781800, 403315183322, 4606767842071, 54959880890476

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Crossrefs

Sequence in context: A309340 A005204 A204428 * A241600 A162112 A162113

Adjacent sequences: A162108 A162109 A162110 * A162112 A162113 A162114

Keyword

nonn

Author

R. H. Hardin, Jun 25 2009

Status

approved