a(1) = 1; a(2) = 2; a(n) == a(k) (mod n-k) for all 1 < k < n.

Terms

a(0) =1a(1) =2a(2) =1a(3) =4a(4) =5a(5) =46a(6) =37a(7) =176a(8) =289a(9) =1450a(10) =641a(11) =24652a(12) =15061a(13) =18734a(14) =110125a(15) =46216a(16) =3137a(17) =1460386a(18) =10506529a(19) =78796820a(20) =77855941a(21) =123250702a(22) =55222421a(23) =3066673744a(24) =54926785a(25) =4846380026a(26) =20185744177a(27) =58863278476a(28) =7499028629