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A237614 Least positive integer k with A000720(k*n) divisible by n, or 0 if such a number k does not exist. 6
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 22 17:35 EST 2019. Contains 320400 sequences. (Running on oeis4.)