OFFSET
1
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A061304(n) mod 2.
EXAMPLE
The eighth squarefree triangular number is 66, which is even, so a(8) = 0.
MAPLE
map(t -> `if`(t-1 mod 4 <= 1, 1, 0), select(t -> numtheory:-issqrfree(t*(t+1)/2), [$1..1000])); # Robert Israel, Oct 09 2017
MATHEMATICA
Boole@ OddQ@ # & /@ Select[PolygonalNumber@ Range@ 210, SquareFreeQ] (* Michael De Vlieger, Oct 06 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Jan 14 2017
STATUS
approved