Floor(n*exp(sec(n))).

Terms

a(0) =6a(1) =0a(2) =1a(3) =0a(4) =169a(5) =17a(6) =26a(7) =0a(8) =3a(9) =3a(11) =39a(12) =39a(13) =21001a(14) =4a(15) =5a(16) =0a(17) =81a(18) =52a(19) =231a(20) =3a(21) =8a(22) =3a(23) =253a(24) =68a(25) =121a(26) =0a(27) =9a(28) =7a(29) =19616a(30) =92