179592

Appears in sequences

• The count of how many queens must be placed tentatively onto a board while seeking a first solution to the "N-Queens on an N x N chessboard" puzzle.at n=20A140450
• E.g.f. satisfies: A(x) = A( x/(1-x)^3 ) * (1-x)/(1+2*x) with A(0)=0.at n=7A261886