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Search: id:A101583
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| A101583 |
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Indices of primes in sequence defined by A(0) = 59, A(n) = 10*A(n-1) - 21 for n > 0. |
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+0
1
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| 0, 1, 2, 9, 24, 28, 33, 72, 75, 76, 650, 883, 937, 1251, 1892, 3341, 4033, 6167, 6215, 6230, 6811, 11045, 15447, 16627, 16917, 18733
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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Numbers n such that (510*10^n + 21)/9 is prime.
Numbers n such that digit 5 followed by n >= 0 occurrences of digit 6 followed by digit 9 is prime.
Numbers corresponding to terms <= 937 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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LINKS
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Makoto Kamada, Factorizations of near-repdigit numbers.
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EXAMPLE
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5669 is prime, hence 2 is a term.
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PROGRAM
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(PARI) a=59; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-21)
(PARI) for(n=0, 1500, if(isprime((510*10^n+21)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A103018(n) - 1.
Adjacent sequences: A101580 A101581 A101582 this_sequence A101584 A101585 A101586
Sequence in context: A091107 A133469 A075714 this_sequence A006002 A023662 A131357
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KEYWORD
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nonn,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 09 2004
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EXTENSIONS
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7 additional terms, corresponding to pseudoprimes, from Ryan Propper (rpropper(AT)stanford.edu), Jun 24 2005. Next term after 6811 is greater than 10,000.
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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