A214059 Least m>0 such that gcd(n^2+1+m, n-m) > 1.

1, 2, 3, 1, 5, 6, 1, 8, 2, 1, 4, 12, 1, 14, 15, 1, 17, 4, 1, 20, 21, 1, 2, 24, 1, 7, 27, 1, 3, 2, 1, 4, 33, 1, 9, 5, 1, 38, 4, 1, 41, 3, 1, 2, 7, 1, 10, 9, 1, 50, 2, 1, 4, 54, 1, 25, 57, 1, 59, 4, 1, 62, 26, 1, 2, 66, 1, 3, 69, 1, 71, 2, 1, 4, 75, 1, 77, 78, 1, 80, 3, 1, 7, 10, 1, 2

Offset

1,2

Links

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

Example

gcd(82+1,9-1) = 1 and gcd(82+2,9-2) = 7, so that a(9) = 2.

Mathematica

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

Crossrefs

Sequence in context: A294223 A355618 A238122 * A195508 A049274 A339470

Adjacent sequences: A214056 A214057 A214058 * A214060 A214061 A214062

Keyword

nonn,easy

Author

Clark Kimberling, Jul 24 2012

Status

approved