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A101079
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Indices of primes in sequence defined by A(0) = 83, A(n) = 10*A(n-1) + 63 for n > 0.
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0
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0, 5, 8, 9, 11, 12, 22, 60, 193, 232, 548, 764, 972, 1060, 1185, 1852, 3712, 6788, 7253, 7764, 9024, 10854
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Numbers n such that (810*10^n - 63)/9 is prime.
Numbers n such that digit 8 followed by n >= 0 occurrences of digit 9 followed by digit 3 is prime.
Numbers corresponding to terms <= 972 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
| 8999993 is prime, hence 5 is a term.
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PROG
| (PARI) a=83; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+63)
(PARI) for(n=0, 1500, if(isprime((810*10^n-63)/9), print1(n, ", ")))
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CROSSREFS
| Cf. A000533, A002275.
a(n) = A103092(n) - 1.
Sequence in context: A205862 A165991 A191977 * A066812 A100832 A034812
Adjacent sequences: A101076 A101077 A101078 * A101080 A101081 A101082
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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), Nov 30 2004
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EXTENSIONS
| More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
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