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Irregular triangle read by rows: T(n,k) (n>=1, 0<=k<=n(n-1)/2) is such that Sum_k T(n,k)*p^(n*(n-1)/2-k) gives the expectation of the number of connected components after deleting every edge of the complete graph on n labeled vertices with probability p.
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%I #17 Mar 13 2022 19:02:17

%S 1,1,1,-1,3,0,1,2,-6,3,4,0,0,1,-6,20,-15,-10,10,0,5,0,0,0,1,24,-90,90,

%T 25,-60,0,-5,15,0,0,6,0,0,0,0,1,-120,504,-630,0,420,-105,0,-105,0,35,

%U -21,21,0,0,0,7,0,0,0,0,0,1,720,-3360,5040,-1176,-3150,1680,140,560,-210,-280,112

%N Irregular triangle read by rows: T(n,k) (n>=1, 0<=k<=n(n-1)/2) is such that Sum_k T(n,k)*p^(n*(n-1)/2-k) gives the expectation of the number of connected components after deleting every edge of the complete graph on n labeled vertices with probability p.

%C Row-reversed version of A125208, see A125208 for further details.

%e Triangle begins:

%e 1;

%e 1, 1;

%e -1, 3, 0, 1;

%e 2, -6, 3, 4, 0, 0, 1;

%e -6, 20, -15, -10, 10, 0, 5, 0, 0, 0, 1;

%e ...

%Y Cf. A125208 (row-reversed version), A127258 (dual version).

%K sign,tabf

%O 1,5

%A _Max Alekseyev_, Jan 09 2007