Number of irregular primes less than e^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =6a(5) =21a(6) =66a(7) =170a(8) =404a(9) =984a(10) =2384a(11) =5877a(12) =14459a(13) =36720a(14) =92657a(15) =234376a(16) =597082a(17) =1525209a(18) =3913689a(19) =10076194a(20) =26016985