a(3)=7个边集:
{{1,2,3}}
{{1},{1,2}}
{{2},{1,2}}
{{1},{2,3}}
{{2},{1,3}}
{{3},{1,2}}
{{1},{2},{3}}
a(4)=28 0-1矩阵的不等价代表:
[1111]
.
[100][1000][010][0100][001][0010][0001][110][110][1100][101][1010][1001]
[111][0111][111][1011][111][1101][1110][101][011][0011][011][0101][0110]
.
[10][100][100][1000][100][100][1000][1000][010][010][0100][0100][0010]
[01][010][010][0100][001][001][0010][0001][001][001][0010][0001][0001]
[11][101][011][0011][110][011][0101][0110][110][101][1001][1010][1100]
.
[1000]
[0100]
[0010]
[0001]
(结束)