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Search: id:A101003
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| A101003 |
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Indices of primes in sequence defined by A(0) = 97, A(n) = 10*A(n-1) - 43 for n > 0. |
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+0
1
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| 0, 2, 3, 14, 152, 321, 470, 560, 663, 2156, 3696
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Numbers n such that (830*10^n + 43)/9 is prime.
Numbers n such that digit 9 followed by n >= 0 occurrences of digit 2 followed by digit 7 is prime.
Numbers corresponding to terms <= 663 are certified primes.
Next term after 3696 is greater than 10000. - Ryan Propper (rpropper(AT)stanford.edu), Jun 21 2005
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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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92227 is prime, hence 3 is a term.
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PROGRAM
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(PARI) a=97; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a-43)
(PARI) for(n=0, 1000, if(isprime((830*10^n+43)/9 ), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275.
a(n) = A103095(n) - 1.
Sequence in context: A041167 A006279 A041521 this_sequence A042071 A042817 A082572
Adjacent sequences: A101000 A101001 A101002 this_sequence A101004 A101005 A101006
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KEYWORD
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nonn,hard,more,less
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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), Nov 27 2004
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EXTENSIONS
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Two more terms, corresponding to probable primes, from Ryan Propper (rpropper(AT)stanford.edu), Jun 21 2005
Edited by T. D. Noe (noe(AT)sspectra.com), Oct 30 2008
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