A120735 - OEIS

%I #3 Dec 15 2017 17:37:04

%S 21,27,97,21,151,163,243,79,313,159,933,197,257,483,313,1049,337,353,

%T 33,217,751,257,1777,193,81,343,647,3,393,737,381,553,709,471,543,

%U 1237,23,699,419,1251,843,953,497,1303,557,1803,841,397,273,681,319,263,231

%N Least positive k such that saw(n) + k is prime, where saw(n) = (1111120*(-1+10^(10*n))/900009).

%C The majority of the decimal expansions of these (probable) primes rise and fall to form a "sawtooth" pattern, e.g. a(3)=97 and saw(3)+97 = 1234565432123456543212345654417. a(1000)=5291. Proof: PFGW Version 1.2.0 for Windows [FFT v23.8] Primality testing (1111120*(-1+10^(10000))/900009)+5291 [N-1/N+1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 2 Running N-1 test using base 3 Running N+1 test using discriminant 11, base 2+sqrt(11) (1111120*(-1+10^(10000))/900009)+5291 is Fermat and Lucas PRP!

%K nonn

%O 1,1

%A _Jason Earls_, Aug 18 2006