%I #18 Jan 17 2019 13:44:06
%S 0,1,2,3,14,26,70,85,104,241,249,447,538,783,813,1024,1171,1352,3008,
%T 3174,3681,6992,7611,7779,9632,27108,27734,28766,61573
%N Indices of primes in sequence defined by A(0) = 97, A(n) = 10*A(n-1) - 33 for n > 0.
%C Numbers n such that (840*10^n + 33)/9 is prime.
%C Numbers n such that digit 9 followed by n >= 0 occurrences of digit 3 followed by digit 7 is prime.
%C Numbers corresponding to terms <= 1024 are certified primes.
%C a(30) > 10^5. - _Robert Price_, Nov 07 2015
%D Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
%H Makoto Kamada, <a href="https://stdkmd.net/nrr/9/93337.htm#prime">Prime numbers of the form 933...337</a>.
%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F a(n) = A103096(n+1) - 1.
%e 9337 is prime, hence 2 is a term.
%t Select[Range[0, 100000], PrimeQ[(840*10^# + 33)/9] &] (* _Robert Price_, Nov 07 2015 *)
%o (PARI) a=97;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a-33)
%o (PARI) for(n=0,1500,if(isprime((840*10^n+33)/9),print1(n,",")))
%Y Cf. A000533, A002275, A103096.
%K nonn,hard,more,less
%O 1,3
%A _Klaus Brockhaus_ and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Nov 27 2004
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 01 2008
%E a(26)-a(28) from Kamada data by _Ray Chandler_, Apr 28 2015
%E a(29) from _Robert Price_, Nov 07 2015
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