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A101840
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Indices of primes in sequence defined by A(0) = 37, A(n) = 10*A(n-1) - 3 for n > 0.
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0
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0, 1, 11, 14, 50, 193, 497, 2135, 2821, 3761, 7427
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| Numbers n such that (330*10^n + 3)/9 is prime.
Numbers n such that digit 3 followed by n >= 0 occurrences of digit 6 followed by digit 7 is prime.
Numbers corresponding to terms <= 497 are certified primes.
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REFERENCES
| Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
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LINKS
| Makoto Kamada, Factorizations of near-repdigit numbers.
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EXAMPLE
| 367 is prime, hence 1 is a term.
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PROG
| (PARI) a=37; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-3)
(PARI) for(n=0, 1500, if(isprime((330*10^n+3)/9), print1(n, ", ")))
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CROSSREFS
| Cf. A000533, A002275.
a(n) = A102975(n) - 1.
Sequence in context: A043105 A043885 A195818 * A061087 A063964 A174952
Adjacent sequences: A101837 A101838 A101839 * A101841 A101842 A101843
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KEYWORD
| nonn,hard,more
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 20 2004
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EXTENSIONS
| More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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