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A118663 Index of the least prime dividing the n-th composite number: A000720(A020639(A002808(n))). 2
1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 3, 1, 2, 1, 1, 1, 2, 1, 3, 1, 1, 2, 1, 1, 1, 2, 1, 1, 4, 1, 2, 1, 1, 3, 1, 2, 1, 1, 1, 2, 1, 3, 1, 1, 2, 1, 1, 1, 2, 1, 4, 1, 1, 2, 1, 1, 3, 1, 2, 1, 1, 4, 1, 2, 1, 3, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 3, 1, 2, 1, 4, 1, 5, 1, 2, 1, 3, 1, 1, 2, 1, 1, 4, 1, 2, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..106.

FORMULA

A118663 = A000720 o A056608. - M. F. Hasler, Apr 03 2012

PROG

(PARI) for(i=2, 999, isprime(i)||print1(primepi(factor(i)[1, 1])", ")) \\ - M. F. Hasler, Apr 03 2012

CROSSREFS

Cf. A056608.

Sequence in context: A161100 A053543 A161099 * A205119 A102097 A050330

Adjacent sequences:  A118660 A118661 A118662 * A118664 A118665 A118666

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, May 19 2006

STATUS

approved

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Last modified August 19 14:06 EDT 2017. Contains 290808 sequences.