b number of minimal primes base b base-b form of largest known minimal prime base b length of largest known minimal prime base b algebraic ((a*bn+c)/d) form of largest known minimal prime base b 2 1 11 2 3 3 3 111 3 13 4 5 221 3 41 5 22 1(0_93)13 96 5^95+8 6 11 40041 5 5209 7 ≥71 (3_16)1 17 (7^17-5)/2 8 75 (4_220)7 221 (4*8^221+17)/7 9 ≥149 3(0_1158)11 1161 3*9^1160+10 10 77 5(0_28)27 31 5*10^30+27 11 ≥914 55(7_1011) 1013 (607*11^1011-7)/10 12 106 4(0_39)77 42 4*12^41+91 13 ≥2496 8(0_32017)111 32021 8*13^32020+183 14 ≥605 4(D_19698) 19699 5*14^19698-1 15 ≥1171 (7_155)97 157 (15^157+59)/2 16 ≥2050 D(B_32234) 32235 (206*16^32234-11)/15