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A078494
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Primes occurring only once in their decade.
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23
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97, 113, 127, 149, 181, 211, 241, 293, 307, 367, 397, 419, 421, 457, 479, 487, 557, 587, 631, 661, 683, 691, 719, 727, 743, 773, 787, 797, 809, 811, 839, 863, 877, 907, 929, 937, 953, 967, 983, 1009, 1021, 1049, 1051, 1087, 1117, 1163, 1171, 1193, 1201, 1249
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OFFSET
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1,1
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LINKS
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FORMULA
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PROG
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(PARI) decade1pr(n1, n2) = { forstep(x=n1, n2, 10, if(isprime(x+1) && !isprime(x+3) && !isprime(x+7) && !isprime(x+9), print1(x+1" "); ); if(isprime(x+3) && !isprime(x+1) && !isprime(x+7) && !isprime(x+9), print1(x+3" "); ); if(isprime(x+7) && !isprime(x+1) && !isprime(x+3) && !isprime(x+9), print1(x+7" "); ); if(isprime(x+9) && !isprime(x+1) && !isprime(x+3) && !isprime(x+7), print1(x+9" "); ); ); }
(Magma) &cat [PrimesInInterval(10*n+1, 10*n+9): n in [0..150] | IsOne(#PrimesInInterval(10*n+1, 10*n+9))]; // Bruno Berselli, Sep 05 2012
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CROSSREFS
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KEYWORD
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nonn,easy,base
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AUTHOR
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STATUS
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approved
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