A298446 - OEIS

%I #26 Mar 28 2019 11:23:38

%S 1,1,2,6,20,1,99,11,1,1,646,149,38,15,1,2,1,0,0,1,5974,3008,1251,542,

%T 171,80,47,12,15,7,4,1,3,0,0,1,0,0,0,1,71885

%N Triangle T(n,k) read by rows: number of n-node connected graphs with rectilinear crossing number k (k=0..A014540(n)).

%C Computed up to n=8 using data provided by Geoffrey Exoo.  (There appear to be some problems with n=9 data.)

%C T(9,1) >= 71335. - _Eric W. Weisstein_, Mar 28 2019

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

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RectilinearCrossingNumber.html">Rectilinear Crossing Number</a>

%F T(n,0) = A003094(n).

%F kmax(n) = A014540(n).

%F T(n,kmax(n)) = 1 for n > 4.

%F sum(k=0..kmax(n), T(n,k)) = A001349(n).

%e Triangle begins:

%e 1

%e 1

%e 2

%e 6

%e 20,1

%e 99,11,1,1

%e 646,149,38,15,1,2,1,0,0,1

%e 5974,3008,1251,542,171,80,47,12,15,7,4,1,3,0,0,1,0,0,0,1

%Y Cf. A014540 (rectilinear crossing number for K_n).

%Y Cf. A298445 (counts for simple graph).

%K nonn,tabf

%O 1,3

%A _Eric W. Weisstein_, Jan 19 2018

%E Corrected by _Eric W. Weisstein_, Mar 28 2019