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A101570
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Indices of primes in sequence defined by A(0) = 53, A(n) = 10*A(n-1) - 17 for n > 0.
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0
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0, 2, 18, 108, 128, 279, 386, 446, 486, 1047, 3297, 3459, 9453
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Numbers n such that (460*10^n + 17)/9 is prime.
Numbers n such that digit 5 followed by n >= 0 occurrences of digit 1 followed by digit 3 is prime.
Numbers corresponding to terms <= 486 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
| 5113 is prime, hence 2 is a term.
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PROG
| (PARI) a=53; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-17)
(PARI) for(n=0, 1500, if(isprime((460*10^n+17)/9), print1(n, ", ")))
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CROSSREFS
| Cf. A000533, A002275.
a(n) = A103005(n) - 1.
Sequence in context: A087291 A005969 A094251 * A006043 A112328 A038721
Adjacent sequences: A101567 A101568 A101569 * A101571 A101572 A101573
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KEYWORD
| nonn,more
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 09 2004
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EXTENSIONS
| More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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