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Search: id:A101074
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| A101074 |
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Indices of primes in sequence defined by A(0) = 83, A(n) = 10*A(n-1) + 33 for n > 0. |
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+0
1
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| 0, 1, 2, 12, 18, 61, 79, 125, 167, 194, 308, 409, 480, 607, 740, 878, 1175, 2687, 6235
(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 (780*10^n - 33)/9 is prime.
Numbers n such that digit 8 followed by n >= 0 occurrences of digit 6 followed by digit 3 is prime.
Numbers corresponding to terms <= 878 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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8663 is prime, hence 2 is a term.
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PROGRAM
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(PARI) a=83; for(n=0, 1200, if(isprime(a), print1(n, ", ")); a=10*a+33)
(PARI) for(n=0, 1200, if(isprime((780*10^n-33)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A103087(n) - 1.
Sequence in context: A120350 A032413 A066238 this_sequence A115109 A048001 A109299
Adjacent sequences: A101071 A101072 A101073 this_sequence A101075 A101076 A101077
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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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