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A085722
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Numbers n such that n^2 + 1 is a semiprime.
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5
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3, 5, 8, 9, 11, 12, 15, 19, 22, 25, 28, 29, 30, 34, 35, 39, 42, 44, 45, 46, 48, 49, 50, 51, 52, 58, 59, 60, 61, 62, 64, 65, 69, 71, 76, 78, 79, 80, 85, 86, 88, 92, 95, 96, 100, 101, 102, 104, 106, 108, 114, 121, 131, 136, 139, 140, 141, 144, 145, 152, 154, 158, 159, 164
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Corresponding semiprimes n^2+1 are in A144255.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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MATHEMATICA
| lst={}; Do[If[Plus@@Last/@FactorInteger[n^2+1]==2, AppendTo[lst, n]], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 24 2009]
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PROG
| (PARI) select(vector(50, n, n), n->bigomega(n^2+1)==2)
\\ Zak Seidov Feb 25 2011
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CROSSREFS
| Sequence in context: A192884 A134427 A065347 * A023980 A189029 A047624
Adjacent sequences: A085719 A085720 A085721 * A085723 A085724 A085725
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KEYWORD
| easy,nonn
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Jul 20 2003
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