OFFSET
1,1
COMMENTS
Since the even anti-tau numbers (A268066) are square numbers, all the terms are either of the form 4*k^2 - 1 or 4*k^2.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
3 is a term since 3 and 4 are both anti-tau numbers: gcd(3, tau(3)) = gcd(3, 2) = 1 and gcd(4, tau(4)) = gcd(4, 3) = 1.
MATHEMATICA
antiTauQ[n_] := CoprimeQ[n, DivisorSigma[0, n]]; s = {}; Do[k = 4*n^2; If[antiTauQ[k], If[antiTauQ[k - 1], AppendTo[s, k - 1]]; If[antiTauQ[k + 1], AppendTo[s, k]]], {n, 1, 50}]; s
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Feb 19 2021
STATUS
approved