reserve a,b,i,k,m,n for Nat;
reserve s,z for non zero Nat;
reserve c for Complex;

theorem Th64:
  1 <= a implies 2|^(2|^z) + (6*a-1) is composite
  proof
    assume
A1: 1 <= a;
    then 6 < 2|^(2|^z) + (6*a-1) by Th61;
    hence 2 <= 2|^(2|^z) + (6*a-1) by XXREAL_0:2;
    thus thesis by A1,Th63;
  end;
