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A324239
Irregular triangle read by rows: T(n,k) is the number of simple connected graphs on n nodes with radius k, (0 <= k <= floor(n/2)).
2
1, 0, 1, 0, 2, 0, 4, 2, 0, 11, 10, 0, 34, 76, 2, 0, 156, 682, 15, 0, 1044, 9864, 207, 2, 0, 12346, 245518, 3197, 19, 0, 274668, 11366961, 74614, 326, 2
OFFSET
1,5
LINKS
Eric Weisstein's World of Mathematics, Graph Radius
EXAMPLE
Triangle begins:
1;
0, 1;
0, 2;
0, 4, 2;
0, 11, 10;
0, 34, 76, 2;
0, 156, 682, 15;
0, 1044, 9864, 207, 2;
0, 12346, 245518, 3197, 19;
0, 274668, 11366961, 74614, 326, 2;
...
CROSSREFS
Row sums give A001349.
Columns k=1..2 are A000088(n-1), A324061.
Sequence in context: A373691 A339941 A211318 * A274706 A037035 A159984
KEYWORD
nonn,tabf,more
AUTHOR
Andrew Howroyd, Sep 02 2019
STATUS
approved