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A128759
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Least k such that the Jacobsthal function A048669(k) = n.
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1
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1, 2, 15, 6, 105, 30, 1155, 770, 36465, 210, 15015, 6006, 255255, 2310, 8580495, 102102, 4849845, 72930
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Except for a(1) and a(2), the same as A070971. It appears that a(2n)=2a(n) for odd n. Because the primorial numbers (A002110) yield record values of the Jacobsthal function, we have a(A048670(n))=A002110(n). Note that numbers in this sequence up to n=18 have the form p#, p#/2, p#/q, or p#/(2q), where p and q are primes with 2<q<p and p# denotes the product of the primes up to p. Other values of a(n) < 10^7: a(22)=30030, a(26)=510510, a(24)=881790 and a(34)=9699690.
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CROSSREFS
| Sequence in context: A193307 A201050 A104773 * A066582 A111329 A059445
Adjacent sequences: A128756 A128757 A128758 * A128760 A128761 A128762
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KEYWORD
| nonn
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AUTHOR
| T. D. Noe (noe(AT)sspectra.com), Mar 28 2007
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