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Search: id:A101729
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| A101729 |
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Indices of primes in sequence defined by A(0) = 41, A(n) = 10*A(n-1) + 51 for n > 0. |
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+0
1
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| 0, 1, 6, 8, 13, 23, 44, 48, 72, 73, 231, 337, 396, 503, 1062, 2816, 5304
(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 (420*10^n - 51)/9 is prime.
Numbers n such that digit 4 followed by n >= 0 occurrences of digit 6 followed by digit 1 is prime.
Numbers corresponding to terms <= 503 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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461 is prime, hence 1 is a term.
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PROGRAM
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(PARI) a=41; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+51)
(PARI) for(n=0, 1500, if(isprime((420*10^n-51)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A102994(n) - 1.
Sequence in context: A047336 A063188 A058938 this_sequence A047451 A101123 A102721
Adjacent sequences: A101726 A101727 A101728 this_sequence A101730 A101731 A101732
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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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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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