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Search: id:A067665
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A067665 The start of a record-setting run of consecutive integers with distinct numbers of prime factors (counted with multiplicity); i.e. let f(n) = A068796(n) be the maximum k such that k consecutive integers starting at n have distinct numbers of prime factors. Then n is in the sequence if f(n) is larger than f(m) for all m such that 1 <= m < n. +0
5
1, 6, 15, 60, 726, 6318, 189375, 755968, 683441871, 33714015615 (list; graph; listen)
OFFSET

1,2

COMMENT

The number of prime factors (counted with multiplicity) of n is bigomega(n) = A001222(n).

For the known terms, f(a(n)) = n+1. Is that true for all n?

EXAMPLE

The values of f(n) for n=1 to 15 are 2,1,2,2,2,3,3,2,1,3,2,3,2,1,4. Records occur at f(1)=2, f(6)=3 and f(15)=4.

MATHEMATICA

bigomega[n_] := Plus@@Last/@FactorInteger[n]; f[n_] := For[k=1; s={bigomega[n]}, True, k++, If[MemberQ[s, z=bigomega[n+k]], Return[k], AppendTo[s, z]]]; For[n=1; max=0, True, n++, If[f[n]>max, Print[n, " ", max=f[n]]]]

CROSSREFS

Cf. A001222, A067650, A068796, A068797.

Sequence in context: A073065 A093042 A145638 this_sequence A012595 A012294 A069750

Adjacent sequences: A067662 A067663 A067664 this_sequence A067666 A067667 A067668

KEYWORD

more,nonn

AUTHOR

G. L. Honaker, Jr. (honak3r(AT)gmail.com), Feb 03 2002

EXTENSIONS

More terms from Shyam Sunder Gupta (guptass(AT)rediffmail.com), Feb 08 2002

Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 20 2002; and by Dean Hickerson (dean.hickerson(AT)yahoo.com), Mar 05 2002

a(10) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 15 2008

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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