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A002187 Sprague-Grundy values for Dawson's Chess (octal game .137).
(Formerly M0025 N0007)
+0
11
0, 1, 1, 2, 0, 3, 1, 1, 0, 3, 3, 2, 2, 4, 0, 5, 2, 2, 3, 3, 0, 1, 1, 3, 0, 2, 1, 1, 0, 4, 5, 2, 7, 4, 0, 1, 1, 2, 0, 3, 1, 1, 0, 3, 3, 2, 2, 4, 4, 5, 5, 2, 3, 3, 0, 1, 1, 3, 0, 2, 1, 1, 0, 4, 5, 3, 7, 4, 8, 1, 1, 2, 0, 3, 1, 1, 0, 3, 3, 2, 2, 4, 4, 5, 5, 9, 3, 3, 0, 1, 1, 3, 0, 2, 1, 1, 0, 4, 5, 3, 7, 4, 8, 1, 1, 2, 0, 3, 1, 1, 0, 3, 3, 2, 2, 4, 4, 5, 5, 9, 3, 3, 0, 1, 1, 3, 0, 2, 1, 1, 0, 4 (list; graph; listen)
OFFSET

0,4

COMMENT

Octal game .07 (Dawson's Kayles) has values a(n-1). Octal games .4, .401, .402, .403, .42, .421, .422 and .423 have values a(n-2).

REFERENCES

E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982, see pp. 89 and 102.

R. K. Guy and C. A. B. Smith, The G-values of various games. Proc. Cambridge Philos. Soc. 52 (1956), 514-526.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

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

LINKS

Achim Flammenkamp, Octal games

FORMULA

Has period 34 with the only exceptions at n=0, 14, 16, 17, 31, 34 and 51.

PROGRAM

{-Haskell-}main=print(tail g); g=0:0:[mex[xor(g!!(a+1))(g!!(n-a-2))|a<-[ -1..n-2]]|n<-[1..]]; xor x y=if(x, y)==(0, 0)then 0 else let((q, r), (s, t))=(divMod x 2, divMod y 2)in(if r==t then 0 else 1)+2*xor q s; mex xs=head[x|x<-[0..], not(elem x xs)] (Paul Stoeber (pstoeber(AT)uni-potsdam.de), Oct 08 2005)

CROSSREFS

Sequence in context: A144257 A074650 A144955 this_sequence A124756 A113504 A124754

Adjacent sequences: A002184 A002185 A002186 this_sequence A002188 A002189 A002190

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Edited by Christian G. Bower (bowerc(AT)usa.net), Oct 22 2002

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Last modified November 22 15:28 EST 2009. Contains 167310 sequences.


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