A162057 Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in nondecreasing order, and no more than 2 ones in any row or column

2, 6, 13, 34, 86, 233, 652, 1888, 5683, 17526, 55868, 182024, 609103, 2081152, 7268823, 25891230, 93983793, 347398900, 1306005890, 4991876362, 19377811110, 76372139937, 305348766558, 1238006401576, 5086973436072

Offset

1,1

Links

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

Crossrefs

Sequence in context: A151390 A116426 A196906 * A026550 A319751 A124124

Adjacent sequences: A162054 A162055 A162056 * A162058 A162059 A162060

Keyword

nonn

Author

R. H. Hardin Jun 25 2009

Status

approved