a(1) = 1, a(2) = 2, a(3) = 3 and a(n) is the smallest number not included earlier that divides the concatenation a(n-3), a(n-2), a(n-1).

A351820

a(1) = 1, a(2) = 2, a(3) = 3 and a(n) is the smallest number not included earlier that divides the concatenation a(n-3), a(n-2), a(n-1).

Terms

    a(0) =1a(1) =2a(2) =3a(3) =41a(4) =2341a(5) =9a(6) =1374473a(7) =7a(8) =123a(9) =13a(10) =49a(11) =53a(12) =91a(13) =689a(14) =5391689a(15) =167a(16) =8429a(17) =17a(18) =11a(19) =21a(20) =211a(21) =37a(22) =89a(23) =2113789a(24) =47a(25) =89211378947a(26) =1336372981a(27) =43a(28) =169a(29) =7213

External references