This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A101714 #15 Jan 17 2019 13:44:06 %S A101714 0,2,8,38,2322 %N A101714 Indices of primes in sequence defined by A(0) = 47, A(n) = 10*A(n-1) - 63 for n > 0. %C A101714 Numbers n such that 40*10^n + 7 is prime. %C A101714 Numbers n such that digit 4 followed by n >= 0 occurrences of digit 0 followed by digit 7 is prime. %C A101714 Some of the larger entries may only correspond to probable primes. %C A101714 a(6) > 2*10^5. - Robert Price May 16 2015 %D A101714 Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467. %H A101714 Makoto Kamada, <a href="https://stdkmd.net/nrr/4/40007.htm#prime">Prime numbers of the form 400...007</a>. %F A101714 a(n) = A101395(n+1) - 1. %e A101714 4007 is prime, hence 2 is a term. %t A101714 Select[Range[0, 3000], PrimeQ[40*10^# + 7] &] (* _Robert Price_, May 16 2015 *) %o A101714 (PARI) a=47;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a-63) %o A101714 (PARI) for(n=0,1500,if(isprime(40*10^n+7),print1(n,","))) %Y A101714 Cf. A000533, A002275, A101395. %K A101714 nonn,hard,more %O A101714 1,2 %A A101714 _Klaus Brockhaus_ and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004