A214061 Least m>0 such that gcd(2*n-1+m, 2*n-m) > 1.

2, 4, 6, 2, 10, 12, 2, 16, 3, 2, 22, 24, 2, 3, 30, 2, 34, 36, 2, 40, 42, 2, 4, 3, 2, 52, 54, 2, 3, 4, 2, 64, 66, 2, 70, 6, 2, 76, 3, 2, 82, 84, 2, 3, 90, 2, 6, 96, 2, 100, 4, 2, 106, 3, 2, 112, 114, 2, 3, 120, 2, 7, 126, 2, 4, 132, 2, 136, 3, 2, 142, 4, 2, 3, 7, 2, 154, 156

Offset

1,1

Links

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

Example

gcd(7+1, 8-1) = 1 and gcd(7+2, 8-2) > 1, so that a(4) = 2.

Mathematica

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

Crossrefs

Cf. A214062.

Sequence in context: A373902 A242593 A094752 * A260300 A182291 A071294

Adjacent sequences: A214058 A214059 A214060 * A214062 A214063 A214064

Keyword

nonn,easy

Author

Clark Kimberling, Jul 25 2012

Status

approved