%I
%S 1,2,11,19,22,26,41,43,44,47,50,53,65,67,68,71,76,79,80,83,94,97,107,
%T 110,113,115,122,124,125,131,134,136,137,145,146,152,155,158,167,169,
%U 170,173,176,181,184,199,202,211,212,226,229,232,233,250,253,254,268,272,274,281,284,286,292,295,298,299
%N Numbers n such that n*10^3+777 is prime.
%C The sequence is infinite, because by Dirichlet's theorem there are infinitely many primes in the arithmetic sequence A*n+B (n=1,2,...) if A an B are relatively prime. [Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009]
%C No term of the sequence is of form 3k, because the sum of digits of 10^3*3k+333=3*(10^3+259) is divisible by 3, violating the requirement of the definition. [Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009]
%e n=1: 1*10^3+777 = 1777 is prime, hence 1 is in the sequence.
%e n=50: 50*10^3+777 = 50777 is prime, hence 50 is in the sequence.
%e n=97: 97*10^3+777 = 97777 is prime, hence 97 is in the sequence.
%o (MAGMA) [ n: n in [0..300]  IsPrime(n*10^3+777) ];
%o (PARI) is(n)=isprime(n*10^3+777) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A157772, A102248, A159942. [Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009]
%K nonn,base,easy
%O 1,2
%A _Parthasarathy Nambi_, Feb 20 2005
%E Extended by Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 27 2009
%E Edited by R. J. Mathar, Apr 30 2009
%E More terms from _Vincenzo Librandi_, May 01 2009
