OFFSET
1,2
COMMENTS
The sequence starts with a(1) = 0 and was always extended with the smallest nonnegative integer not yet present that does not lead to a contradiction.
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..7162
EXAMPLE
As a(1) = 0, a(2) cannot be an odd term: thus a(2) = 2 (the smallest available nonnegative even integer); now as a(3) and a(4) must be odd integers we have a(3) = 1 and a(4) = 3 (again, the smallest available nonnegative odd integers); now a(5) = 4, forcing the next 4 integers to be odd, thus a(6) = 5, a(7) = 7, a(8) = 9 and a(9) = 11; etc.
MATHEMATICA
Table[Prepend[2 Range[# (# + 1) + 1, # (# + 1) + 2 n] &@ (n - 1) - 1, 2 n], {n, 0, 8}] // Flatten (* Michael De Vlieger, Oct 12 2016 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Oct 12 2016
STATUS
approved