A214058 Least m>0 such that gcd(3^n+m,2^n-m) > 1.

2, 4, 1, 16, 2, 3, 3, 1, 1, 10, 3, 22, 2, 4, 1, 1675, 2, 1, 3, 1, 1, 10, 3, 1, 2, 4, 1, 81, 2, 12, 3, 788, 1, 10, 3, 75, 2, 4, 1, 1, 2, 12, 3, 1, 1, 10, 3, 192, 2, 4, 1, 16, 2, 1, 3, 1, 1, 10, 3, 1, 2, 4, 1, 361, 2, 3, 3, 1, 1, 10, 3, 1, 1, 4, 1, 81, 2, 12, 3, 1042, 1, 10, 3, 1, 2

Offset

1,1

Links

Clark Kimberling, Table of n, a(n) for n = 1..500

Example

gcd(9+1,4-1) = gcd(9+2,4-2) = gcd(9+3, 4-3) = 1 and gcd(9+4, 4-4) > 1, so that a(2) = 4.

Mathematica

b[n_] := 3^n; c[n_] := 2^n; Table[m = 1; While[GCD[b[n] + m, c[n] - m] == 1, m++]; m, {n, 150}]

Crossrefs

Cf. A214056.

Sequence in context: A172385 A081538 A224783 * A173820 A030043 A045497

Adjacent sequences: A214055 A214056 A214057 * A214059 A214060 A214061

Keyword

nonn,easy

Author

Clark Kimberling, Jul 24 2012

Status

approved