OFFSET
1,3
FORMULA
a(k^2 + k) = 0, a(k^2 + k - 1) = 2*k, a(k^2 + k + 1) = a(k^2) = 2*k + 1
EXAMPLE
a(5) = 4 because (5; 1; 1) -> (3; 1; 3) -> (1; 3; 3) -> (5; 1; = -1) -> (5; 1; 1) : length of cycle =4.
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Deléham, Sep 24 2003
STATUS
approved