A214717 Least m>0 such that 4^n-m and n-m are relatively prime.

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

Clark Kimberling, Table of n, a(n) for n = 1..1000

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

Adjacent sequences: A214714 A214715 A214716 * A214718 A214719 A214720

Keyword

nonn,easy

Author

Clark Kimberling, Jul 27 2012

Status

approved