A006021 The game of contours. (Formerly M0409)

0, 1, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2, 3, 1, 4, 3, 2, 0, 5, 2

Offset

0,3

References

E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982, see p. 553.

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

Links

Table of n, a(n) for n=0..82.

Formula

a(0) = 0, b(1) = 0, a(n) = mex({a(s) ^ b(t): s+t = n-1 and s>0} union {b(s) + b(t): s+t = n-1}), b(n) = mex({a(s) ^ b(t): s+t = n-1 and s>0}) with ^ denoting bitwise addition. - Sean A. Irvine, Dec 14 2016

a(n+8) = a(n) for n >= 6. - Sean A. Irvine, Dec 14 2016

Crossrefs

Sequence in context: A011857 A242360 A299927 * A002186 A125936 A243614

Adjacent sequences: A006018 A006019 A006020 * A006022 A006023 A006024

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Sean A. Irvine, Dec 14 2016

Status

approved