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A107286 a(0) = 0; for n>0, minimal prime factor of n, or 1 if n is 1 or a prime. 1
0, 1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 5, 2, 3, 2, 1, 2, 1, 2, 3, 2, 5, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 2, 7, 2, 3, 2, 1, 2, 5, 2, 3, 2, 1, 2, 1, 2, 3, 2, 5, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 7, 2, 1, 2, 3, 2, 1, 2, 5, 2, 3, 2, 1, 2, 7, 2, 3, 2, 5, 2, 1, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..20000

PROG

(PARI) a(n) = if (n==0, 0, if (n==1, 1, if (isprime(n), 1, factor(n)[1, 1]))) \\ Michel Marcus, Jun 03 2013

CROSSREFS

Cf. A020639.

Sequence in context: A248470 A082067 A082061 * A087039 A102096 A322813

Adjacent sequences:  A107283 A107284 A107285 * A107287 A107288 A107289

KEYWORD

nonn,look

AUTHOR

Giovanni Teofilatto, May 20 2005

STATUS

approved

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Last modified May 23 18:45 EDT 2019. Contains 323528 sequences. (Running on oeis4.)