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Search: id:A101714
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| A101714 |
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Indices of primes in sequence defined by A(0) = 47, A(n) = 10*A(n-1) - 63 for n > 0. |
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1
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OFFSET
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1,2
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COMMENT
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Numbers n such that 40*10^n + 7 is prime.
Numbers n such that digit 4 followed by n >= 0 occurrences of digit 0 followed by digit 7 is prime.
Some of the larger entries may only correspond to probable primes.
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REFERENCES
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Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
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EXAMPLE
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4007 is prime, hence 2 is a term.
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PROGRAM
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(PARI) a=47; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-63)
(PARI) for(n=0, 1500, if(isprime(40*10^n+7), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A101395(n) - 1.
Sequence in context: A058786 A096654 A060389 this_sequence A077318 A082014 A154133
Adjacent sequences: A101711 A101712 A101713 this_sequence A101715 A101716 A101717
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KEYWORD
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nonn,hard,more
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AUTHOR
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Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004
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