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 A101585 Indices of primes in sequence defined by A(0) = 53, A(n) = 10*A(n-1) + 43 for n > 0. 0
 0, 3, 11, 14, 17, 36, 108, 1727, 2481, 3479, 6576, 9014 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers n such that (520*10^n - 43)/9 is prime. Numbers n such that digit 5 followed by n >= 0 occurrences of digit 7 followed by digit 3 is prime. Numbers corresponding to terms <= 108 are certified primes. REFERENCES Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467. LINKS EXAMPLE 57773 is prime, hence 3 is a term. PROG (PARI) a=53; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a+43) (PARI) for(n=0, 1000, if(isprime((520*10^n-43)/9), print1(n, ", "))) CROSSREFS Cf. A000533, A002275. a(n) = A103020(n) - 1. Sequence in context: A176049 A186078 A063963 * A115214 A143029 A186701 Adjacent sequences:  A101582 A101583 A101584 * A101586 A101587 A101588 KEYWORD nonn,more AUTHOR Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 09 2004 EXTENSIONS Five additional terms, corresponding to probable primes, from Ryan Propper (rpropper(AT)stanford.edu), Jun 22 2005 Edited by T. D. Noe, Oct 30 2008 STATUS approved

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