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Search: id:A001092
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| A001092 |
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Union of all numbers {p, q} where p and q are both primes or powers of primes and q = p+2. |
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+0
1
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| 1, 2, 3, 4, 5, 7, 9, 11, 13, 17, 19, 23, 25, 27, 29, 31, 41, 43, 47, 49, 59, 61, 71, 73, 79, 81, 83, 101, 103, 107, 109, 125, 127, 137, 139, 149, 151, 167, 169, 179, 181, 191, 193, 197, 199, 227, 229, 239, 241, 243, 269, 271, 281, 283, 311, 313, 347, 349, 359, 361, 419
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 844.
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LINKS
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
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PROGRAM
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(PARI) {isprimepower(n)=matsize(factor(n))[1]==1} for(n=1, 400, if(isprimepower(n)&&(isprimepower(n-2)||isprimepower(n+2)), print1(n", "))) (from Ralf Stephan, Aug 20 2004)
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CROSSREFS
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Cf. A053702, A074852.
Sequence in context: A063487 A081998 A074583 this_sequence A000430 A166684 A067126
Adjacent sequences: A001089 A001090 A001091 this_sequence A001093 A001094 A001095
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 14, 2001
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