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 A006067 Number of ways to quarter an n X n chessboard. (Formerly M3769) 5
 1, 1, 1, 5, 7, 37, 104, 766, 3970, 43318, 431932, 7695805, 137066448, 4015896016, 128095791922, 6371333036059, 355704307903818, 30153126159555641, 2952926822418475378, 431453249608567040694, 73569487283165427567144, 18558756256964594960321428 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS See A257952 for much more information. See A272070 for information on odd terms. REFERENCES M. Gardner, The Unexpected Hanging and Other Mathematical Diversions. Simon and Schuster, NY, 1969, p. 189. Popular Computing, Vol. 1 (No. 7, 1973), front cover and page 2. T. R. Parkin, personal communication. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Andrew Howroyd, Table of n, a(n) for n = 1..28 FORMULA a(2n) = A257952(n), a(2n+1) = A272070(n). - Andrew Howroyd, Apr 19 2016 CROSSREFS Cf. A257952, A064941, A272070. Sequence in context: A081851 A192156 A322380 * A244260 A178428 A147760 Adjacent sequences:  A006064 A006065 A006066 * A006068 A006069 A006070 KEYWORD nonn,nice AUTHOR EXTENSIONS a(8) corrected, a(9)-a(22) from Andrew Howroyd, Apr 18 2016 STATUS approved

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Last modified February 17 18:14 EST 2020. Contains 332005 sequences. (Running on oeis4.)