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A086435 Maximum number of parts possible in a factorization of n into a product of distinct numbers > 1. +0
4
0, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 2, 3, 1, 2, 2, 3, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 3, 2, 3, 2, 2, 1, 3, 1, 2, 2, 3, 2, 3, 1, 2, 2, 3, 1, 3, 1, 2, 2, 2, 2, 3, 1, 3, 2, 2, 1, 3, 2, 2, 2, 3, 1, 3, 2, 2, 2, 2, 2, 3, 1, 2, 2, 3, 1, 3 (list; graph; listen)
OFFSET

1,6

COMMENT

For n>1, a((n+1)!) = n is the first occurrence of n in the sequence. This function depends only on the prime signature of n. - Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Dec 19 2006

LINKS

Eric Weisstein's World of Mathematics, UnorderedFactorization

EXAMPLE

a(6)=2 since 6 may be factored into distinct parts as {{2,3},{6}}, so the largest number of factors possible is 2.

a(8)=2 since 8 may be factored into distinct parts as {{8},{2,4}}, so the largest numbers of factors possible is 2.

PROGRAM

(PARI) { a(n, m=1) = if(n>m, 1 + vecmax( apply( x->if(x>m, a(n/x, x)), divisors(n) ))) } [From Max Alekseyev (maxale(AT)gmail.com), Jul 16 2009]

CROSSREFS

Cf. A000142, A025487.

Sequence in context: A065031 A058061 A064547 this_sequence A099305 A033109 A111627

Adjacent sequences: A086432 A086433 A086434 this_sequence A086436 A086437 A086438

KEYWORD

nonn

AUTHOR

Eric Weisstein (eric(AT)weisstein.com), Jul 19, 2003

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Last modified December 17 23:40 EST 2009. Contains 171025 sequences.


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