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A101133
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Indices of primes in sequence defined by A(0) = 71, A(n) = 10*A(n-1) + 11 for n > 0.
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0
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0, 3, 15, 24, 28, 40, 46, 87, 1131, 1569, 3984
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Numbers n such that (650*10^n - 11)/9 is prime.
Numbers n such that digit 7 followed by n >= 0 occurrences of digit 2 followed by digit 1 is prime.
Some of the larger entries may only correspond to probable 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
| 72221 is prime, hence 3 is a term.
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PROG
| (PARI) a=71; for(n=0, 1200, if(isprime(a), print1(n, ", ")); a=10*a+11)
(PARI) for(n=0, 1200, if(isprime((650*10^n-11)/9), print1(n, ", ")))
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CROSSREFS
| Cf. A000533, A002275.
a(n) = A103052(n) - 1.
Sequence in context: A009210 A142882 A161467 * A061386 A057780 A129024
Adjacent sequences: A101130 A101131 A101132 * A101134 A101135 A101136
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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 03 2004
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EXTENSIONS
| More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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