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Number of ways to quarter an n X n chessboard.
(Formerly M3769)
5

%I M3769 #32 Nov 19 2016 19:25:34

%S 1,1,1,5,7,37,104,766,3970,43318,431932,7695805,137066448,4015896016,

%T 128095791922,6371333036059,355704307903818,30153126159555641,

%U 2952926822418475378,431453249608567040694,73569487283165427567144,18558756256964594960321428

%N Number of ways to quarter an n X n chessboard.

%C See A257952 for much more information.

%C See A272070 for information on odd terms.

%D M. Gardner, The Unexpected Hanging and Other Mathematical Diversions. Simon and Schuster, NY, 1969, p. 189.

%D Popular Computing, Vol. 1 (No. 7, 1973), front cover and page 2.

%D T. R. Parkin, personal communication.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Andrew Howroyd, <a href="/A006067/b006067.txt">Table of n, a(n) for n = 1..28</a>

%H <a href="/A003213/a003213.jpg">Illustration showing that a(6) = 37.</a>

%F a(2n) = A257952(n), a(2n+1) = A272070(n). - _Andrew Howroyd_, Apr 19 2016

%Y Cf. A257952, A064941, A272070.

%K nonn,nice

%O 1,4

%A _N. J. A. Sloane_

%E a(8) corrected, a(9)-a(22) from _Andrew Howroyd_, Apr 18 2016