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%I #23 Jul 06 2019 16:44:21
%S 797,911,1287,2127,2217,2247,2303,2457,2841,3221,3407,3531,3921,4353,
%T 4361,4403,5097,5459,5867,6173,6261,6531,6741,6939,7133,7271,7311,
%U 7707,7797,8651,8841,8951,9347,9401,9599,9669,9729,10001,10773,10937,11663
%N Numbers n such that googol - n is prime.
%C This sequence is finite with between 4.361969*10^97 and 4.361998*10^97 terms. Under the Riemann Hypothesis, it has 4.361971987140703159099509113229164611538757211...*10^97 terms. - _Charles R Greathouse IV_, Nov 23 2009
%C 10^100-a(148) and 10^100-a(149) are the last twin primes less than 10^100. - _T. D. Noe_, Nov 03 2008
%H T. D. Noe, <a href="/A108251/b108251.txt">Table of n, a(n) for n = 1..1000</a>
%H For each of the 1000 terms in the table, 10^100 - a(n) was verified by the <a href="http://magma.maths.usyd.edu.au/calc/">Magma Calculator</a> as prime. - _Jon E. Schoenfield_, Aug 24 2009
%e A googol = 10^100. 10^100 - 797 is prime, so 797 is in the sequence.
%t Rest[10^100-#&/@NestList[NextPrime[#,-1]&,10^100,50]] (* _Harvey P. Dale_, Jan 23 2017 *)
%o (PARI) forstep(x=1,n,2,if(isprime(10^100-x),print1(x",")))
%Y Cf. A049014, A133282.
%K easy,nonn,fini
%O 1,1
%A _Cino Hilliard_, Jun 17 2005
%E Edited by _Charles R Greathouse IV_, Nov 23 2009
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