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A055019
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Numbers n such that A051885(p_n) is prime, where p_n=A000040(n) is the n-th prime.
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1
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1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 20, 22, 25, 40, 41, 55, 57, 64, 77, 125, 663, 1053, 1414, 1711, 2822, 2956, 4107, 7463
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OFFSET
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1,2
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COMMENTS
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Numbers n such that A051885(A000040(n)) = A054750(n).
No other terms below 10^4.
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LINKS
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Table of n, a(n) for n=1..30.
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EXAMPLE
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The 125th prime is 691. The least integer with sum of digits 691 is A051885(691) = 8*10^76-1 which is prime. This is the 22nd prime with this property, so a(22)=125.
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PROG
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(PARI) for(X=1, 300, a=prime(X)%9; b=prime(X)\9; m=(a+1)*10^b-1; if(isprime(m), print([X, prime(X), m]) ) )
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CROSSREFS
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Cf. A054750, A051885.
Sequence in context: A129511 A174905 A191849 * A172152 A218444 A014122
Adjacent sequences: A055016 A055017 A055018 * A055020 A055021 A055022
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KEYWORD
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more,nonn,base
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AUTHOR
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Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), May 31 2000
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EXTENSIONS
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More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jun 22 2001
a(27)-a(30) from Max Alekseyev, Dec 09 2011
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STATUS
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approved
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