A369279 Triangle read by rows: T(n,k) is the number of simple graphs on n unlabeled nodes with cooling number k = 1..n.

1, 0, 2, 0, 2, 2, 0, 3, 6, 2, 0, 3, 22, 7, 2, 0, 4, 102, 41, 7, 2, 0, 4, 661, 322, 48, 7, 2, 0, 5, 7606, 4238, 439, 49, 7, 2, 0, 5, 169021, 98708, 6396, 480, 49, 7, 2, 0, 6, 7555003, 4282954, 159359, 7301, 487, 49, 7, 2

Offset

1,3

Links

Table of n, a(n) for n=1..55.

Eric Weisstein's World of Mathematics, Cooling Number.

Eric Weisstein's World of Mathematics, Simple Graph.

Example

Triangle begins:
  1;
  0, 2;
  0, 2,       2;
  0, 3,       6,       2;
  0, 3,      22,       7,      2;
  0, 4,     102,      41,      7,    2;
  0, 4,     661,     322,     48,    7,   2;
  0, 5,    7606,    4238,    439,   49,   7,  2;
  0, 5,  169021,   98708,   6396,  480,  49,  7, 2;
  0, 6, 7555003, 4282954, 159359, 7301, 487, 49, 7, 2;
  ...

Crossrefs

Rows sums are A000088.

Cf. A369280 (counts for connected graphs), A263322 (burning number).

Sequence in context: A121363 A346274 A214258 * A138021 A166065 A252706

Adjacent sequences: A369276 A369277 A369278 * A369280 A369281 A369282

Keyword

nonn,tabl,more

Author

_Eric W. Weisstein_, Jan 18 2024

Status

approved