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 A101735 Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) + 53 for n > 0. 1
 0, 3, 9, 11, 12, 39, 75, 122, 500, 647, 3540, 4001, 4227, 5270, 7431, 27305, 43401 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers n such that (440*10^n - 53)/9 is prime. Numbers n such that digit 4 followed by n >= 0 occurrences of digit 8 followed by digit 3 is prime. Numbers corresponding to terms <= 647 are certified primes. a(18) > 10^5. - Robert Price, Jun 01 2015 REFERENCES Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467. LINKS Table of n, a(n) for n=1..17. Makoto Kamada, Prime numbers of the form 488...883. Index entries for primes involving repunits. FORMULA a(n) = A102998(n) - 1. EXAMPLE 48883 is prime, hence 3 is a term. MATHEMATICA Select[Range[0, 1000], PrimeQ[(440*10^# - 53)/9] &] (* Robert Price, Jun 01 2015 *) PROG (PARI) a=43; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+53) (PARI) for(n=0, 1500, if(isprime((440*10^n-53)/9), print1(n, ", "))) CROSSREFS Cf. A000533, A002275, A102998. Sequence in context: A174565 A074261 A059868 * A101620 A235583 A287333 Adjacent sequences: A101732 A101733 A101734 * A101736 A101737 A101738 KEYWORD nonn,hard,more AUTHOR Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004 EXTENSIONS More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008 a(16)-a(17) from Kamada data by Ray Chandler, May 01 2015 STATUS approved

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Last modified December 1 09:00 EST 2023. Contains 367469 sequences. (Running on oeis4.)