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Search: id:A005265
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| A005265 |
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a(1)=3, b(n)=Product_{k=1..n} a(k), a(n+1)=smallest prime factor of b(n)-1.
(Formerly M2246)
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+0
41
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| 3, 2, 5, 29, 11, 7, 13, 37, 32222189, 131, 136013303998782209, 31, 197, 19, 157, 17, 8609, 1831129, 35977, 508326079288931, 487, 10253, 1390043, 18122659735201507243, 25319167, 9512386441, 85577, 1031, 3650460767, 107, 41, 811, 15787, 89, 68168743, 4583, 239, 1283, 443, 902404933, 64775657, 2753, 23, 149287, 149749, 7895159, 79, 43, 1409, 184274081, 47, 569, 63843643
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Suggested by Euclid's proof that there are infinitely many primes.
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
R. K. Guy and R. Nowakowski, ``Discovering primes with Euclid,'' Delta (Waukesha), Vol. 5, pp. 49-63, 1975.
S. S. Wagstaff, Jr., Computing Euclid's primes, Bull. Institute Combin. Applications, 8 (1993), 23-32.
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LINKS
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Sean A. Irvine (sairvin(AT)xtra.co.nz) added terms 54 through 61, May 21 2006, giving Table of n, a(n) for n = 1..61
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CROSSREFS
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Cf. A000945, A000946, A005266, A084599.
Essentially the same as A084598.
Adjacent sequences: A005262 A005263 A005264 this_sequence A005266 A005267 A005268
Sequence in context: A077039 A103938 A085973 this_sequence A005266 A005267 A016460
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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