OFFSET
1,2
COMMENTS
This sequence encodes in binary the parity of the divisors of a number.
For any n > 0, the binary representation of a(n) corresponds to the n-th row of A247795.
For any n > 0, n and a(n) have the same parity.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
Rémy Sigrist, Colored logarithmic scatterplot of the first 100000 terms (where the color is function of A000005(n))
FORMULA
MATHEMATICA
Array[FromDigits[Mod[#, 2] & /@ Divisors@ #, 2] &, 69] (* Michael De Vlieger, Feb 18 2018 *)
PROG
(PARI) a(n) = fromdigits(apply(d -> d%2, divisors(n)), 2)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Feb 18 2018
STATUS
approved