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A094499
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Smallest prime factor of 2^(2^n)+3^(2^n), i.e. exponents are powers of 2.
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2
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13, 97, 17, 3041, 1153, 769, 257, 72222721, 4043777, 2330249132033, 625483777, 286721, 14496395542529, 2752513, 65537, 319291393, 54498164737
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OFFSET
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1,1
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COMMENTS
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Factors are of the form k*2^(n+1)+1.
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REFERENCES
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Anders Bjorn and Hans Riesel, Factors of Generalized Fermat Numbers, Mathematics of Computation, Vol. 67, Nbr 221, Pgs 441-446, 1998.
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LINKS
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Table of n, a(n) for n=1..17.
Dario Alejandro Alpern, Factorization using the Elliptic Curve Method.
Anders Bjorn and Hans Riesel, Factors of Generalized Fermat numbers..
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MATHEMATICA
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f[n_] := Block[{k = 1, m = 2^(n + 1)}, While[ Mod[ PowerMod[2, 2^n, k*m + 1] + PowerMod[3, 2^n, k*m + 1], k*m + 1] != 0, k++ ]; k*m + 1]; Table[ f[n], {n, 9}] (from Robert G. Wilson v Jun 03 2004)
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CROSSREFS
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Sequence in context: A044645 A153703 A222503 * A141894 A160554 A211388
Adjacent sequences: A094496 A094497 A094498 * A094500 A094501 A094502
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jun 02 2004
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EXTENSIONS
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Edited and extended by Robert G. Wilson v, Jun 03 2004
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STATUS
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approved
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