
theorem
  3881 is prime
proof
  now
    3881 = 2*1940 + 1; hence not 2 divides 3881 by NAT_4:9;
    3881 = 3*1293 + 2; hence not 3 divides 3881 by NAT_4:9;
    3881 = 5*776 + 1; hence not 5 divides 3881 by NAT_4:9;
    3881 = 7*554 + 3; hence not 7 divides 3881 by NAT_4:9;
    3881 = 11*352 + 9; hence not 11 divides 3881 by NAT_4:9;
    3881 = 13*298 + 7; hence not 13 divides 3881 by NAT_4:9;
    3881 = 17*228 + 5; hence not 17 divides 3881 by NAT_4:9;
    3881 = 19*204 + 5; hence not 19 divides 3881 by NAT_4:9;
    3881 = 23*168 + 17; hence not 23 divides 3881 by NAT_4:9;
    3881 = 29*133 + 24; hence not 29 divides 3881 by NAT_4:9;
    3881 = 31*125 + 6; hence not 31 divides 3881 by NAT_4:9;
    3881 = 37*104 + 33; hence not 37 divides 3881 by NAT_4:9;
    3881 = 41*94 + 27; hence not 41 divides 3881 by NAT_4:9;
    3881 = 43*90 + 11; hence not 43 divides 3881 by NAT_4:9;
    3881 = 47*82 + 27; hence not 47 divides 3881 by NAT_4:9;
    3881 = 53*73 + 12; hence not 53 divides 3881 by NAT_4:9;
    3881 = 59*65 + 46; hence not 59 divides 3881 by NAT_4:9;
    3881 = 61*63 + 38; hence not 61 divides 3881 by NAT_4:9;
  end;
  then for n being Element of NAT st 1 < n & n*n <= 3881 & n is prime
  holds not n divides 3881 by XPRIMET1:36;
  hence thesis by NAT_4:14;
end;
