20201019, 15:45  #1 
Nov 2016
2347_{10} Posts 
757
757 is irregular prime
757 is de Polignac number (cannot be written as 2^n+p with prime p) 757 is the smallest prime p such that 1/p has period length 3^3 (in decimal) The smallest n such that Phi_n(k,k1) is prime is 414, where k is 757 (this is the largest for k<=1024) (there are only 3 nvalues <=1024 such that Phi_n(k,k1) is prime, and both of them are even, where k is 757) (if we require n is prime, then the smallest n is 96487) There is no known prime of the form (b1)*b^n+1 with n>=1, where b is 757 The smallest known prime of the form b*(b+1)^n1 is very large, where b is 757 
20201019, 20:33  #2 
Jul 2018
Martin, Slovakia
3^{3}·7 Posts 
