Number of cousin primes < 10^n.

Terms

a(0) =2a(1) =9a(2) =41a(3) =203a(4) =1216a(5) =8144a(6) =58622a(7) =440258a(8) =3424680a(9) =27409999a(10) =224373161a(11) =1870585459a(12) =15834656003a(13) =135779962760