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A068405
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Numbers n such that (n+1) is squarefree and composite and such that there is one more distinct prime factor in n than in (n+1).
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0
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84, 90, 105, 110, 114, 132, 140, 154, 165, 182, 186, 204, 220, 234, 246, 252, 258, 264, 266, 273, 286, 290, 294, 300, 308, 318, 322, 340, 345, 354, 357, 364, 370, 380, 385, 402, 406, 410, 414, 426, 444, 450, 465, 468, 470, 480, 492, 504, 516, 518, 525, 532
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| For example 322=2*7*23 has 3 distinct prime factors and 323=17*19 has 2 distinct prime factors, hence 322 is in the sequence.
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FORMULA
| n such that (1-isprime(n+1))*issquarefree(n+1)*omega(n)=omega(n+1)+1
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CROSSREFS
| Sequence in context: A033404 A128873 A095607 * A045569 A113931 A111313
Adjacent sequences: A068402 A068403 A068404 * A068406 A068407 A068408
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KEYWORD
| easy,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 09 2002
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