%I
%S 0,0,8,34,105,248,490,858,1379,2080,2988,4130,5533,7224,9230,11578,
%T 14295,17408,20944,24930,29393,34360,39858,45914,52555,59808,67700,
%U 76258,85509,95480,106198,117690,129983,143104,157080,171938,187705
%N Number of ways to place 3 nonattacking kings on a 3 X n board.
%H Vincenzo Librandi, <a href="/A172202/b172202.txt">Table of n, a(n) for n = 1..1000</a>
%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing nonattacking queens and kings on boards of various sizes</a>
%F a(n) = (n2)*(9n^245n+70)/2, n>=2.
%F G.f.: x^3*(17*x^2+2*x+8)/(x1)^4.  _Vaclav Kotesovec_, Mar 24 2010
%t CoefficientList[Series[x^2 (17 x^2 + 2 x + 8) / (x  1)^4, {x, 0, 50}], x] (* _Vincenzo Librandi_, May 27 2013 *)
%Y Cf. A061996, A061989, A047659.
%K nonn,easy
%O 1,3
%A _Vaclav Kotesovec_, Jan 29 2010
%E More terms from _Vincenzo Librandi_, May 27 2013
