%I A102011
%S A102011 0,2,5,50,56,62,149,392,419,546
%N A102011 Indices of primes in sequence defined by A(0) = 19, A(n) = 10*A(n-1) 
               - 61 for n > 0.
%C A102011 Numbers n such that (110*10^n + 61)/9 is prime.
%C A102011 Numbers n such that digit 1 followed by n >= 0 occurrences of digit 2 
               followed by digit 9 is prime.
%C A102011 Numbers corresponding to terms <= 546 are certified primes.
%D A102011 Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, 
               MNU 59/8 (2006), pp. 462-467.
%e A102011 1222229 is prime, hence 5 is a term.
%o A102011 (PARI) a=19;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a-61)
%o A102011 (PARI) for(n=0,1500,if(isprime((110*10^n+61)/9),print1(n,",")))
%Y A102011 Cf. A000533, A002275.
%Y A102011 a(n) = A102931(n) - 1.
%Y A102011 Sequence in context: A112266 A060808 A099658 this_sequence A004098 A005114 
               A081090
%Y A102011 Adjacent sequences: A102008 A102009 A102010 this_sequence A102012 A102013 
               A102014
%K A102011 nonn,hard,more
%O A102011 1,2
%A A102011 Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp 
               (oberschelp(AT)informatik.rwth-aachen.de), Dec 28 2004