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A083848
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a(n)^2 + 1 is largest prime of the form x^2 + 1 <= 2^n.
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5
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1, 1, 2, 2, 4, 6, 10, 14, 20, 26, 40, 56, 90, 126, 180, 250, 350, 496, 716, 1010, 1440, 2034, 2896, 4086, 5774, 8184, 11566, 16380, 23166, 32766, 46326, 65534, 92666, 131070, 185354, 262130, 370714, 524260, 741454, 1048554, 1482904, 2097146
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| It is conjectured that this sequence is infinite, but this has never been proved.
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REFERENCES
| G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, th. 17.
P. Ribenboim, The Little Book of Big Primes. Springer-Verlag, 1991, p. 190.
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LINKS
| Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. Landau's Problems.
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CROSSREFS
| Cf. A005574, A002496, A083844, A083845, A083846, A083847, A083849.
Sequence in context: A060988 A034406 A098330 * A139582 A034410 A192682
Adjacent sequences: A083845 A083846 A083847 * A083849 A083850 A083851
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KEYWORD
| nonn
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AUTHOR
| Harry J. Smith (hjsmithh(AT)sbcglobal.net), May 05 2003
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