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Search: id:A101730
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| A101730 |
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Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) + 33 for n > 0. |
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1
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| 0, 1, 2, 3, 5, 6, 7, 11, 22, 58, 74, 143, 203, 267, 759, 1215, 1429, 1505, 1508, 2803, 2923, 3200, 3304, 5752, 9267, 11278, 19676
(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 - 33)/9 is prime.
Numbers n such that digit 4 followed by n >= 0 occurrences of digit 6 followed by digit 3 is prime.
Numbers corresponding to terms <= 759 are certified primes.
a(n) = A099005(n) - 1.
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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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463 is prime, hence 1 is a term.
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PROGRAM
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(PARI) a=43; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+33)
(PARI) for(n=0, 1500, if(isprime((420*10^n-33)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275, A099005.
Sequence in context: A098959 A071251 A077571 this_sequence A039058 A046158 A070274
Adjacent sequences: A101727 A101728 A101729 this_sequence A101731 A101732 A101733
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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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