OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
9 is a term since all of its divisors, 1, 3 and 9, or 1, 111, and 11001 in negabinary representation, have an odd number of 1's.
MATHEMATICA
negaBinWt[n_] := negaBinWt[n] = If[n==0, 0, negaBinWt[Quotient[n-1, -2]] + Mod[n, 2]]; odNegaBinQ[n_] := OddQ[negaBinWt[n]]; seqQ[n_] := AllTrue[Divisors[n], odNegaBinQ]; Select[Range[401], seqQ]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Jan 28 2020
STATUS
approved