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Triangle read by rows: T(n,k) is the number of simple graphs on n unlabeled nodes with cooling number k = 1..n.
2

%I #26 Mar 11 2024 23:12:54

%S 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,

%T 7606,4238,439,49,7,2,0,5,169021,98708,6396,480,49,7,2,0,6,7555003,

%U 4282954,159359,7301,487,49,7,2

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

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CoolingNumber.html">Cooling Number</a>.

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SimpleGraph.html">Simple Graph</a>.

%e Triangle begins:

%e 1;

%e 0, 2;

%e 0, 2, 2;

%e 0, 3, 6, 2;

%e 0, 3, 22, 7, 2;

%e 0, 4, 102, 41, 7, 2;

%e 0, 4, 661, 322, 48, 7, 2;

%e 0, 5, 7606, 4238, 439, 49, 7, 2;

%e 0, 5, 169021, 98708, 6396, 480, 49, 7, 2;

%e 0, 6, 7555003, 4282954, 159359, 7301, 487, 49, 7, 2;

%e ...

%Y Rows sums are A000088.

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

%K nonn,tabl,more

%O 1,3

%A _Eric W. Weisstein_, Jan 18 2024