# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a101716 Showing 1-1 of 1 %I A101716 #15 Jan 17 2019 13:44:06 %S A101716 0,3,4,12,30,54,57,58,60,78,90,102,120,195,228,9438,13050,22959,31296 %N A101716 Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) - 17 for n > 0. %C A101716 Numbers n such that (370*10^n + 17)/9 is prime. %C A101716 Numbers n such that digit 4 followed by n >= 0 occurrences of digit 1 followed by digit 3 is prime. %C A101716 Numbers corresponding to terms <= 228 are certified primes. %C A101716 a(20) > 10^5. - _Robert Price_, May 08 2015 %D A101716 Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467. %H A101716 Makoto Kamada, Prime numbers of the form 411...113. %H A101716 Index entries for primes involving repunits. %F A101716 a(n) = A102981(n) - 1. %e A101716 41113 is prime, hence 3 is a term. %t A101716 Select[Range[0, 300], PrimeQ[(370*10^# + 17)/9] &] (* _Robert Price_, May 08 2015 *) %o A101716 (PARI) a=43;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a-17) %o A101716 (PARI) for(n=0,1500,if(isprime((370*10^n+17)/9),print1(n,","))) %Y A101716 Cf. A000533, A002275, A102981. %K A101716 nonn,hard,more %O A101716 1,2 %A A101716 _Klaus Brockhaus_ and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004 %E A101716 9438 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008 %E A101716 a(17)-a(19) from Kamada data by _Ray Chandler_, Apr 30 2015 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE