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A070295

Smallest composite number such that there are exactly n primes less than it (and coprime to it) which do not divide it, or 0 if no such number exists.

4, 10, 8, 14, 16, 20, 24, 25, 33, 32, 0, 44, 48, 49, 66, 62, 64, 72, 74, 80, 81, 91, 98, 105, 104, 108, 111, 115, 121, 128, 140, 141, 154, 152, 158, 164, 171, 169, 182, 183, 192, 194, 204, 200, 212, 224, 230, 232, 235, 246, 242, 243, 256, 265, 273, 272, 278, 285

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OFFSET

1,1

COMMENTS

Are there any zero values other than a(11) = 0?

Conjecture: a(223) = 0. - Sean A. Irvine, Jun 07 2024

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

a(4) = 14: primes up to 14 are 2, 3, 5, 7, 11, 13 out of which four primes 3, 5, 11 and 13 are coprime to 14.

CROSSREFS

Sequence in context: A080362 A365781 A298400 * A123483 A320577 A199805