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Search: id:A068678
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| A068678 |
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Number which yields a prime when a 9 is prefixed or suffixed to it. |
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+0
1
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| 7, 19, 37, 41, 47, 71, 83, 91, 103, 127, 157, 161, 187, 199, 203, 209, 239, 257, 281, 293, 311, 349, 371, 377, 391, 413, 421, 433, 463, 467, 479, 491, 511, 539, 547, 551, 587, 619, 629, 661, 677, 689, 721, 749, 769, 787, 791, 803, 817, 859, 871, 883, 923
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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127 is a member as 1279 as well as 9127 both are primes.
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MAPLE
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i := 0:for k from 1 to 3200 do if(isprime(9+10*k) and isprime(k+10^(ceil(evalf(log(k+1)/log(10))))*9)) then s[i] := k; i := i+1; end if; end do:q := seq(s[j], j=0..i-1);
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CROSSREFS
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Cf. A068673, A068674, A068677.
Sequence in context: A165333 A154878 A124270 this_sequence A069833 A031337 A152540
Adjacent sequences: A068675 A068676 A068677 this_sequence A068679 A068680 A068681
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KEYWORD
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base,easy,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 02 2002
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EXTENSIONS
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More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 17 2002
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