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Search: id:A118573
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| A118573 |
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Sophie Germain primes for which the reversal is also a Sophie Germain prime. |
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| 2, 3, 5, 11, 131, 191, 359, 953, 1229, 1583, 3851, 9221, 10061, 11579, 11939, 12119, 12821, 13619, 14081, 14741, 14939, 15791, 15803, 16001, 16883, 18041, 19163, 19391, 19751, 19991, 30851, 31859, 32633, 33623, 33809, 35993, 36191, 36563
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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{k such that k is in A005384 and A004086(k) is in A005384}. - Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 18 2008
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EXAMPLE
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359 is in the sequence because (1) it is a Sophie Germain prime and (2) the reversal 953 is also a Sophie Germain prime.
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MATHEMATICA
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Select[Prime[Range[10000]], PrimeQ[2*# + 1] && PrimeQ[FromDigits[Reverse[ IntegerDigits[ # ]]]] && PrimeQ[2*FromDigits[Reverse[IntegerDigits[ # ]]] + 1] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 18 2008
fQ[n_] := (rp = FromDigits@ Reverse@ IntegerDigits@n; PrimeQ[2n + 1] && PrimeQ[rp] && PrimeQ[2rp + 1]); Select[Prime@ Range@4093, fQ@# &] - Robert G. Wilson v (rgwv(at)rgwv.com), May 09 2006
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CROSSREFS
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Cf. A004086, A005384.
Sequence in context: A050444 A117701 A056163 this_sequence A051835 A075883 A127814
Adjacent sequences: A118570 A118571 A118572 this_sequence A118574 A118575 A118576
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KEYWORD
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base,nonn
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AUTHOR
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Luc Stevens (lms022(AT)yahoo.com), May 07 2006
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com) and Adam Panagos (adam.panagos(AT)gmail.com), May 09 2006
Edited by N. J. A. Sloane, Mar 02 2009 at the suggestion of R. J. Mathar
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