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 A101577 Indices of primes in sequence defined by A(0) = 59, A(n) = 10*A(n-1) - 51 for n > 0. 1
 0, 46, 68, 98, 574, 714, 2178, 10540 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers n such that (480*10^n + 51)/9 is prime. Numbers n such that digit 5 followed by n >= 0 occurrences of digit 3 followed by digit 1 is prime. Numbers corresponding to terms <= 714 are certified primes. a(9) > 10^5. - Robert Price, Sep 08 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..8. Makoto Kamada, Prime numbers of the form 533...339. Index entries for primes involving repunits. FORMULA a(n) = A103012(n+1) - 1. EXAMPLE 59 is prime, hence 0 is a term. MATHEMATICA Select[Range[0, 10000], PrimeQ[(480*10^# + 51)/9] &] (* Robert Price, Sep 08 2015 *) PROG (PARI) a=59; for(n=0, 1000, if(isprime(a), print1(n, ", ")); a=10*a-51) (PARI) for(n=0, 1000, if(isprime((480*10^n+51)/9), print1(n, ", "))) CROSSREFS Cf. A000533, A002275, A103012. Sequence in context: A118698 A350203 A103381 * A051413 A167283 A085434 Adjacent sequences: A101574 A101575 A101576 * A101578 A101579 A101580 KEYWORD nonn,more AUTHOR Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 09 2004 EXTENSIONS More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008 a(8) from Kamada data by Ray Chandler, Apr 30 2015 STATUS approved

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Last modified June 24 00:02 EDT 2024. Contains 373661 sequences. (Running on oeis4.)