A316665 a(n) is the least k > 0 such that k*n does not belong to A002202.

3, 7, 1, 17, 1, 15, 1, 19, 1, 5, 1, 43, 1, 1, 1, 19, 1, 5, 1, 17, 1, 7, 1, 167, 1, 1, 1, 11, 1, 3, 1, 19, 1, 1, 1, 67, 1, 1, 1, 17, 1, 17, 1, 7, 1, 5, 1, 211, 1, 1, 1, 7, 1, 11, 1, 13, 1, 3, 1, 139, 1, 1, 1, 31, 1, 9, 1, 1, 1, 5, 1, 109, 1, 1, 1, 1, 1, 3, 1

Offset

1,1

Comments

All terms are odd.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Scatterplot of (x, y) such that 1 <= x, y <= 500 and x*y does not belong to A002202

Formula

a(n) = 1 iff n belongs to A007617.

Prog

(PARI) a(n) = forstep (k=1, oo, 2, if (!istotient(n*k), return (k)))

Crossrefs

Cf. A002202, A007617.

Sequence in context: A210037 A210197 A324715 * A110238 A077505 A309376

Adjacent sequences: A316662 A316663 A316664 * A316666 A316667 A316668

Keyword

nonn

Author

Rémy Sigrist, Jul 10 2018

Status

approved