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Search: id:A101736
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| A101736 |
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Indices of primes in sequence defined by A(0) = 47, A(n) = 10*A(n-1) + 17 for n > 0. |
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+0
1
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| 0, 1, 6, 13, 24, 115, 426, 594, 636, 775, 1705
(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 (440*10^n - 17)/9 is prime.
Numbers n such that digit 4 followed by n >= 0 occurrences of digit 8 followed by digit 7 is prime.
Numbers corresponding to terms <= 775 are certified primes.
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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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EXAMPLE
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487 is prime, hence 1 is a term.
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MATHEMATICA
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For[n=0, n<= 3000, n++, If[PrimeQ[(440*10^n - 17)/9], Print[n]]] (Steinerberger)
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PROGRAM
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(PARI) a=47; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+17)
(PARI) for(n=0, 1500, if(isprime((440*10^n-17)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A102999(n) - 1.
Sequence in context: A032528 A058535 A131833 this_sequence A162432 A117072 A081395
Adjacent sequences: A101733 A101734 A101735 this_sequence A101737 A101738 A101739
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KEYWORD
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nonn,hard
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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 14 2004
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EXTENSIONS
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a(11) from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Feb 04 2006
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