a(n) = floor(exp(n/Pi)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =6a(6) =9a(7) =12a(8) =17a(9) =24a(10) =33a(11) =45a(12) =62a(13) =86a(14) =118a(15) =162a(16) =223a(17) =307a(18) =423a(19) =581a(20) =799a(21) =1099a(22) =1511a(23) =2078a(24) =2857a(25) =3928a(26) =5401a(27) =7425a(28) =10208a(29) =14034