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Search: id:A108818
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| A108818 |
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Primes such that the outer 2 digits are n and n+1 and all inner digits are 1, where 0 < n < 9. |
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+0
1
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| 617, 2113, 81119, 21111113, 81111119, 8111111119, 21111111111113, 81111111111111111119, 81111111111111111111119, 2111111111111111111111113, 2111111111111111111111111111113, 611111111111111111111111111111117
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(x) = 10^(x+1)*n+floor(10^x/9)*10+n+1. Output if a(x) is prime.
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PROGRAM
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(PARI) n10np1(n) = { local(x, y, k); for(x=1, n, for(k=1, 8, y=10^(x+1)*k+floor(10^x/9)*10+k+1; if(isprime(y), print1(y", ")) ) ) }
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CROSSREFS
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Adjacent sequences: A108815 A108816 A108817 this_sequence A108819 A108820 A108821
Sequence in context: A032657 A117503 A025329 this_sequence A020377 A118467 A133207
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KEYWORD
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easy,nonn,base
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Jul 11 2005
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