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Search: id:A101964
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| A101964 |
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Indices of primes in sequence defined by A(0) = 23, A(n) = 10*A(n-1) + 33 for n > 0. |
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+0
1
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| 0, 1, 2, 4, 5, 6, 10, 20, 29, 67, 72, 168, 175, 344, 822, 1020, 1190, 2072, 2754, 10716, 14672, 16753, 17605
(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 (240*10^n - 33)/9 is prime.
Numbers n such that digit 2 followed by n >= 0 occurrences of digit 6 followed by digit 3 is prime.
Numbers corresponding to terms <= 822 are certified primes.
a(n) = A098959(n-1) - 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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263 is prime, hence 1 is a term.
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PROGRAM
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(PARI) a=23; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+33)
(PARI) for(n=0, 1500, if(isprime((240*10^n-33)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275, A098959.
a(n) = A098959(n) - 1.
Sequence in context: A043045 A091678 A080053 this_sequence A129305 A113631 A101951
Adjacent sequences: A101961 A101962 A101963 this_sequence A101965 A101966 A101967
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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 23 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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