Number of primes <= n-th Catalan number.

Terms

a(0) =0a(1) =0a(2) =1a(3) =3a(4) =6a(5) =13a(6) =32a(7) =82a(8) =226a(9) =651a(10) =1939a(11) =5946a(12) =18637a(13) =59736a(14) =194898a(15) =645742a(16) =2167325a(17) =7359262a(18) =25237989a(19) =87325031a(20) =304549332a(21) =1069685013a(22) =3781189896a(23) =13443608964a(24) =48049822995a(25) =172568075048a(26) =622514907195