cp's OEIS Frontend

A101730 Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) + 33 for n > 0.

%I A101730 #15 Jan 17 2019 13:44:06
%S A101730 0,1,2,3,5,6,7,11,22,58,74,143,203,267,759,1215,1429,1505,1508,2803,
%T A101730 2923,3200,3304,5752,9267,11278,19676,23413,28626,31361,42298,49118,
%U A101730 63746,81766
%N A101730 Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) + 33 for n > 0.
%C A101730 Numbers n such that (420*10^n - 33)/9 is prime.
%C A101730 Numbers n such that digit 4 followed by n >= 0 occurrences of digit 6 followed by digit 3 is prime.
%C A101730 Numbers corresponding to terms <= 759 are certified primes.
%C A101730 a(35) > 10^5. - _Robert Price_, Mar 30 2015
%D A101730 Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
%H A101730 Makoto Kamada, <a href="https://stdkmd.net/nrr/4/46663.htm#prime">Prime numbers of the form 466...663</a>.
%H A101730 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.
%F A101730 a(n) = A099005(n) - 1.
%e A101730 463 is prime, hence 1 is a term.
%t A101730 Select[Range[0, 100], PrimeQ[(420*10^# - 33)/9] &]
%o A101730 (PARI) a=43;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a+33)
%o A101730 (PARI) for(n=0,1500,if(isprime((420*10^n-33)/9),print1(n,",")))
%Y A101730 Cf. A000533, A002275, A099005.
%K A101730 nonn,hard,more
%O A101730 1,3
%A A101730 _Klaus Brockhaus_ and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 14 2004
%E A101730 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
%E A101730 a(28)-a(34) derived from A099005 by _Robert Price_, Mar 30 2015