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A137715 Prime values of n for which n*2^k + 1 is composite for all positive integers k. 5
271129, 322523, 327739, 482719, 934909, 1639459, 2131043, 2131099, 2576089, 3098059, 3608251, 4573999, 6678713, 6799831, 7523281, 7761437, 8184977, 8840599, 8879993, 8959163, 9208337, 9252323, 9930469, 9937637, 10192733, 10306187, 10391933, 11206501 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The sequence contains those members of A076336 that are prime.
Note that the terms in A076336 are presently conjectural. - Joerg Arndt, Jun 29 2015
LINKS
Arkadiusz Wesolowski, Table of n, a(n) for n = 1..3670
R. Baillie, G. Cormack, and H. C. Williams, The Problem of Sierpinski Concerning k*2^n+1, Mathematics of Computation, Vol. 37, No. 155 (July 1981), pp. 229-231. Corrigenda; Mathematics of Computation, Vol. 39, No. 159 (July 1982), p. 308.
Wilfrid Keller, Factors of Fermat Numbers and Large Primes of the Form k*2^n+1, Mathematics of Computation, Vol. 41, No. 164 (October 1983), pp. 661-673.
W. Sierpinski, Sur un problème concernant les nombres k*2^n+1, Elem. d. Math. 15, pp. 73-74, 1960.
EXAMPLE
As 271129 is the first known prime value of n for which n*2^k + 1 is composite for all positive integers k, a(1) = 271129.
CROSSREFS
Sequence in context: A257647 A206001 A244561 * A258893 A237181 A013998
KEYWORD
nonn
AUTHOR
Ant King, Feb 09 2008
EXTENSIONS
More terms from Arkadiusz Wesolowski, Apr 24 2012
STATUS
approved

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Last modified May 23 13:40 EDT 2024. Contains 372763 sequences. (Running on oeis4.)