A162110 Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in strictly increasing order, and no more than 2 ones in any row or column

2, 4, 8, 21, 53, 145, 405, 1180, 3562, 11030, 35306, 115338, 387443, 1326992, 4650201, 16604351, 60443887, 223971602, 844095896, 3234044019, 12582749734, 49703821584, 199149007691, 809153896365, 3331563584486

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Crossrefs

Sequence in context: A340595 A216643 A002040 * A108071 A337762 A055876

Adjacent sequences: A162107 A162108 A162109 * A162111 A162112 A162113

Keyword

nonn

Author

R. H. Hardin Jun 25 2009

Status

approved