A056255 Indices of primes in sequence defined by A(0) = 33, A(n) = 10*A(n-1) + 43 for n > 0.
1, 13, 53, 67, 83, 85, 155, 2765, 3379, 3875, 5207, 10745, 15767, 31315, 40957, 45803, 46565, 51007, 80161
Offset: 1
Examples
373 is prime, hence 1 is a term.
References
- Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
Links
- Patrick De Geest, PDP Reference Table - 373.
- Makoto Kamada, Prime numbers of the form 377...773.
- Index entries for primes involving repunits.
Programs
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Mathematica
Select[Range[0, 2000], PrimeQ[(340 10^# - 43) / 9] &] (* Vincenzo Librandi, Nov 03 2014 *)
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PARI
a=33;for(n=0,1500,if(isprime(a),print1(n,","));a=10*a+43)
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PARI
for(n=0,1500,if(isprime((340*10^n-43)/9),print1(n,",")))
Formula
a(n) = A082708(n) - 2.
Extensions
Additional comments from Klaus Brockhaus and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 20 2004
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 15 2007
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
Two more terms from PDP table and a link added, and comments section updated, by Patrick De Geest, Nov 02 2014
Edited by Ray Chandler, Nov 05 2014
Comments