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A006067

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

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

Illustration showing that a(6) = 37.

FORMULA

a(2n) = A257952(n), a(2n+1) = A272070(n). - Andrew Howroyd, Apr 19 2016

CROSSREFS

Cf. A257952, A064941, A272070.

Sequence in context: A342504 A192156 A322380 * A244260 A178428 A147760

Adjacent sequences: A006064 A006065 A006066 * A006068 A006069 A006070

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

a(8) corrected, a(9)-a(22) from Andrew Howroyd, Apr 18 2016

STATUS

approved