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A214717
Least m>0 such that 4^n-m and n-m are relatively prime.
2
2, 1, 1, 3, 1, 3, 2, 1, 1, 3, 1, 1, 2, 1, 2, 3, 1, 1, 2, 1, 1, 3, 1, 1, 2, 5, 1, 3, 1, 1, 2, 1, 1, 3, 1, 3, 2, 1, 1, 3, 1, 1, 2, 1, 2, 3, 1, 1, 2, 1, 1, 3, 1, 1, 2, 3, 2, 3, 1, 1, 2, 1, 1, 3, 1, 3, 2, 1, 1, 3, 1, 1, 2, 1, 1, 3, 1, 3, 2, 1, 1, 3, 1, 1, 2, 3, 1
OFFSET
1,1
LINKS
EXAMPLE
gcd(4^6-1,5) = 5, gcd(4^6-2,4) = 2, gcd(4^6-3,3) = 1, so a(6) = 3.
MATHEMATICA
Table[m = 1; While[GCD[4^n - m, n - m] != 1, m++]; m, {n, 1, 140}]
CROSSREFS
Cf. A214716.
Sequence in context: A121560 A326409 A326408 * A293312 A136405 A210871
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jul 27 2012
STATUS
approved