A345248 Number of labeled connected simple graphs on n vertices without cycles of length 4.

1, 1, 4, 28, 302, 4776, 106732, 3249352, 131290812, 6922560160, 470586936176, 40833342324864, 4482709905772936, 617622136930640128, 106013904370382120400, 22516967955697072408576, 5880701545642715236590608, 1877504184190590494772860928

Offset: 1

Author

Brendan McKay, Jun 12 2021

Keywords

• nonn
• hard

Comments

From R. J. Mathar, Apr 03 2022 (Start)

The sequence contains the row sums of the number of labeled connected simple graphs on V vertices with E edges, the triangle with V>=0, E>=0:

1 ;

1 ;

0 1;

0 0 3 1;

0 0 0 16 12;

0 0 0 0 125 162 15;

0 0 0 0 0 1296 2580 900;

0 0 0 0 0 0 16807 47715 35595 6615 ;

0 0 0 0 0 0 0 262144 1006488 1270080 619920 90720;

0 0 0 0 0 0 0 0 4782969 23859108 44893170 39867660 15892065 1995840 ;

(End)

Crossrefs

LOG transform of A345249.

A077269 counts isomorphism classes.

Cf. A345218.