OFFSET
1,3
FORMULA
a(n) = n^2 - A261928(n).
EXAMPLE
a(2) = 1 because only the pair (1,1) mod 2 doesn't exist as result from any (x*y,x+y) mod 2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Thomas Kerscher, Sep 06 2015
STATUS
approved