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A325447
Triangle read by rows: T(n,k) is the number of nonseparable (or 2-connected) graphs on n unlabeled nodes with circumference k, (n >= 3, k >= 3).
2
1, 0, 3, 0, 2, 8, 0, 2, 6, 48, 0, 2, 9, 74, 383, 0, 2, 10, 159, 756, 6196, 0, 2, 13, 276, 2058, 14634, 177083, 0, 2, 14, 505, 4824, 48137, 384942, 9305118
OFFSET
3,3
LINKS
Eric Weisstein's World of Mathematics, Graph Circumference
Eric Weisstein's World of Mathematics, Hamiltonian Graph
FORMULA
T(n, 4) = 2 for n > 4.
EXAMPLE
Triangle begins, (n >= 3, k >= 3):
1;
0, 3;
0, 2, 8;
0, 2, 6, 48;
0, 2, 9, 74, 383;
0, 2, 10, 159, 756, 6196;
0, 2, 13, 276, 2058, 14634, 177083;
0, 2, 14, 505, 4824, 48137, 384942, 9305118;
...
CROSSREFS
Row sums are A002218(n >= 3).
Right diagonal is A003216.
Sequence in context: A303410 A126671 A209437 * A240660 A347418 A330646
KEYWORD
nonn,tabl,more
AUTHOR
Andrew Howroyd, Sep 06 2019
STATUS
approved