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A345248
Number of labeled connected simple graphs on n vertices without cycles of length 4.
2
1, 1, 4, 28, 302, 4776, 106732, 3249352, 131290812, 6922560160, 470586936176, 40833342324864, 4482709905772936, 617622136930640128, 106013904370382120400, 22516967955697072408576, 5880701545642715236590608, 1877504184190590494772860928
OFFSET
1,3
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.
Sequence in context: A372738 A274043 A007152 * A295258 A177554 A316212
KEYWORD
nonn,hard
AUTHOR
Brendan McKay, Jun 12 2021
STATUS
approved