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Search: id:A101078
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| A101078 |
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Indices of primes in sequence defined by A(0) = 89, A(n) = 10*A(n-1) - 11 for n > 0. |
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+0
1
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| 0, 2, 5, 30, 35, 60, 116, 228, 338, 3164, 3957, 5276, 5342, 6078, 6534, 8484
(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 (790*10^n + 11)/9 is prime.
Numbers n such that digit 8 followed by n >= 0 occurrences of digit 7 followed by digit 9 is prime.
Numbers corresponding to terms <= 338 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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8777779 is prime, hence 5 is a term.
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PROGRAM
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(PARI) a=89; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a-11)
(PARI) for(n=0, 1000, if(isprime((790*10^n+11)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A103091(n) - 1.
Sequence in context: A086383 A118612 A158866 this_sequence A109739 A163800 A019027
Adjacent sequences: A101075 A101076 A101077 this_sequence A101079 A101080 A101081
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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), Nov 30 2004
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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