OFFSET
1,1
COMMENTS
Complement of A263647.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
gcd(2^4-1, 3^4-1) = gcd(15,80) = 5, so a(1) = 4.
MATHEMATICA
Select[Range[200], ! GCD[2^# - 1, 3^# - 1] == 1 &]
PROG
(Magma) [n: n in [1..200] | not Gcd(2^n-1, 3^n-1) eq 1];
(PARI) isok(n) = gcd(2^n-1, 3^n-1) != 1; \\ Michel Marcus, May 01 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, May 01 2016
STATUS
approved