A201507 - OEIS

%I #11 Apr 11 2024 14:00:30

%S 0,0,0,20,12798,763144,15516804,170842828,1264750240,7084450248,

%T 32251861624,125030824732,426265242412,1308045124808,3675893768908,

%U 9586626461484,23445303141400,54219244028296,119372323892736,251614892723068,510130577706724,998740710435208

%N Number of ways to place 7 nonattacking wazirs on an n X n board.

%C Wazir is a leaper [0,1].

%H V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>

%F Explicit formula: n^14/5040 - n^12/48 + n^11/60 + 137*n^10/144 - 3*n^9/2 - 1139*n^8/48 + 223*n^7/4 + 59293*n^6/180 - 3191*n^5/3 - 8719*n^4/4 + 51737*n^3/5 + 10914*n^2/7 - 40708*n + 37228, n>=6.

%F G.f.: 2*x^4*(5*x^16 - 31*x^15 + 193*x^14 - 1683*x^13 + 5093*x^12 + 12431*x^11 - 111239*x^10 + 214181*x^9 + 187845*x^8 - 1518841*x^7 + 2546483*x^6 - 775465*x^5 - 6212549*x^4 - 2702167*x^3 - 286637*x^2 - 6249*x - 10)/(x-1)^15.

%F a(n) = A232833(n,7). - _R. J. Mathar_, Apr 11 2024

%Y Cf. A172225, A172226, A172227, A172228, A178409.

%K nonn

%O 1,4

%A _Vaclav Kotesovec_, Dec 02 2011