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%I #9 Sep 18 2018 02:41:31
%S 1,2,3,6,17,54,153,552,2057,8394,35539,166926,856189,4674890,27358553,
%T 171129072,1141190303,8017021932,59365844491,461939618824
%N Number of nodes of the backtrack tree for the n queens problem.
%D D. E. Knuth, The Art of Computer Programming, Volume 4, Pre-fascicle 5B, Introduction to Backtracking, 7.2.2. Backtrack programming. 2018.
%Y Row sums of A319284.
%Y Cf. A000170.
%K nonn,more
%O 0,2
%A _Peter Luschny_, Sep 16 2018