OFFSET
2,1
COMMENTS
A156989 is the main sequence for this entry. Related to the density Hales-Jewett theorem.
LINKS
Steve Landsburg, Blogging, Tic Tac Toe and the Future of Math
FORMULA
a(n) = 3^n - A156989(n).
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Charles R Greathouse IV, Sep 26 2011
STATUS
approved