A237614 Least positive integer k with A000720(k*n) divisible by n, or 0 if such a number k does not exist.

1, 2, 2, 2, 6, 11, 11, 7, 3, 3, 3, 8, 13, 13, 8, 14, 14, 14, 33, 33, 9, 15, 9, 4, 4, 42, 22, 22, 43, 4, 36, 99, 10, 10, 10, 10, 38, 38, 38, 38, 31, 24, 17, 17, 17, 62, 24, 194, 55, 80, 11, 40, 11, 11, 11, 11, 11, 57, 11, 11, 33, 18, 18, 83, 164, 5, 5, 5, 156, 5

Offset

1,2

Comments

According to the conjecture in A237597, we should always have 0 < a(n) < prime(n).

Links

Zhi-Wei Sun, Table of n, a(n) for n = 1..10000

Example

a(3) = 2 since pi(2*3) = 3 is divisible by 3, but pi(1*3) = 2 is not.

Mathematica

Do[Do[If[Mod[PrimePi[k*n], n]==0, Print[n, " ", k]; Goto[aa]], {k, 1, Prime[n]-1}];
Print[n, " ", 0]; Label[aa]; Continue, {n, 1, 70}]

Crossrefs

Cf. A000720, A237578, A237597, A237598, A237612.

Sequence in context: A032306 A227847 A058756 * A257255 A248765 A007039

Adjacent sequences: A237611 A237612 A237613 * A237615 A237616 A237617

Keyword

nonn

Author

Zhi-Wei Sun, Feb 10 2014

Status

approved