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A085152
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Sequence related to ABC conjecture: All prime factors of n and n+1 are <= 5.
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21
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OFFSET
| 1,2
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COMMENTS
| The ABC conjecture would imply that if the prime factors of A, B, C are prescribed in advance, then there is only a finite number of solutions to the equation A + B = C with gcd(A,B,C)=1 (indeed it would bound C to be no more than "roughly" the product of those primes). So in particular there ought to be only finitely many pairs of adjacent integers whose prime factors are limited to {2, 3, 5} (D. Rusin).
This sequence is complete by a theorem of Stormer. See A002071. - T. D. Noe (noe(AT)sspectra.com), Mar 03 2008
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MATHEMATICA
| Select[Range[10000], FactorInteger[ # (# + 1)][[ -1, 1]] <= 5 &] - T. D. Noe (noe(AT)sspectra.com), Mar 03 2008
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CROSSREFS
| Cf. A085153.
Sequence in context: A204810 A194714 A054168 * A015931 A120430 A152606
Adjacent sequences: A085149 A085150 A085151 * A085153 A085154 A085155
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KEYWORD
| nonn,fini,full
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 21 2003
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EXTENSIONS
| Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Jun 30 2003
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