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 A102006 Indices of primes in sequence defined by A(0) = 13, A(n) = 10*A(n-1) - 27 for n > 0. 5
 0, 1, 4, 5, 10, 16, 17, 38, 55, 100, 104, 106, 122, 412, 425, 2606, 7667, 10469, 11020, 17752, 26926, 60775, 98287, 300475 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Numbers n such that 10*10^n + 3 is prime. Numbers n such that digit 1 followed by n >= 0 occurrences of digit 0 followed by digit 3 is prime. Numbers corresponding to terms <= 425 are certified primes. No other terms <99,999. REFERENCES Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467. LINKS Makoto Kamada, Prime numbers of the form 100...003. FORMULA a(n) = A049054(n) - 1. EXAMPLE 100003 is prime, hence 4 is a term. PROG (PARI) a=13; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a-27) (PARI) for(n=0, 1500, if(isprime(10*10^n+3), print1(n, ", "))) CROSSREFS Cf. A000533, A002275, A049054, A159352. Sequence in context: A135104 A131780 A354968 * A118735 A002970 A073611 Adjacent sequences: A102003 A102004 A102005 * A102007 A102008 A102009 KEYWORD nonn,hard,more AUTHOR Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 28 2004 EXTENSIONS More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008 a(22)=60775, a(23)=98287 from Robert Price, Mar 03 2011 a(24) from A049054 by Ray Chandler, May 01 2015 STATUS approved

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Last modified January 29 23:01 EST 2023. Contains 359939 sequences. (Running on oeis4.)