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Search: id:A101519
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| A101519 |
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Indices of primes in sequence defined by A(0) = 63, A(n) = 10*A(n-1) - 17 for n > 0. |
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+0
1
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| 1, 2, 4, 10, 11, 22, 74, 100, 121, 172, 646, 2014, 2683
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Numbers n such that (550*10^n + 17)/9 is prime.
Numbers n such that digit 6 followed by n >= 0 occurrences of digit 1 followed by digit 3 is prime.
Numbers corresponding to terms <= 646 are certified 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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611113 is prime, hence 4 is a term.
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PROGRAM
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(PARI) a=63; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a-17)
(PARI) for(n=0, 1000, if(isprime((550*10^n+17)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A103027(n) - 1.
Adjacent sequences: A101516 A101517 A101518 this_sequence A101520 A101521 A101522
Sequence in context: A056376 A136818 A029984 this_sequence A138940 A129412 A121926
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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 06 2004
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 06 2007
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