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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.
0
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
OFFSET
1,1
COMMENTS
Are there any zero values other than a(11) = 0?
Conjecture: a(223) = 0. - Sean A. Irvine, Jun 07 2024
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 A073722 A320577
KEYWORD
nonn
AUTHOR
Amarnath Murthy, May 10 2002
EXTENSIONS
Corrected and extended by Larry Reeves (larryr(AT)acm.org), Oct 01 2002
STATUS
approved