a(n) = floor(gamma^(-n)) where gamma is Euler's constant A001620.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =9a(5) =15a(6) =27a(7) =46a(8) =81a(9) =140a(10) =243a(11) =421a(12) =731a(13) =1266a(14) =2194a(15) =3801a(16) =6585a(17) =11409a(18) =19765a(19) =34243a(20) =59325a(21) =102777a(22) =178058a(23) =308477a(24) =534423a(25) =925864a(26) =1604017a(27) =2778888a(28) =4814297a(29) =8340552