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A128759 Least k such that the Jacobsthal function A048669(k) = n. +0
2
1, 2, 15, 6, 105, 30, 1155, 770, 36465, 210, 15015, 6006, 255255, 2310, 8580495, 102102, 4849845, 72930 (list; graph; listen)
OFFSET

1,2

COMMENT

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.

CROSSREFS

Sequence in context: A106484 A027739 A104773 this_sequence A066582 A111329 A059445

Adjacent sequences: A128756 A128757 A128758 this_sequence A128760 A128761 A128762

KEYWORD

nonn

AUTHOR

T. D. Noe (noe(AT)sspectra.com), Mar 28 2007

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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