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)).

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

Author

Andrew Howroyd, Sep 02 2019

Keywords

• nonn
• tabf
• more

Examples

			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;
  ...
		

Links

• Eric Weisstein's World of Mathematics, Graph Radius
• Wikipedia, Distance (graph theory)

Crossrefs

Row sums give A001349.

Columns k=1..2 are A000088(n-1), A324061.

Cf. A283826, A294522, A294525, A324244.