a(1) = 1; for n>1, a(n) = floor(sqrt(a(n-1))) if that number is not already in the sequence, otherwise a(n) = 3*a(n-1).

A213912

a(1) = 1; for n>1, a(n) = floor(sqrt(a(n-1))) if that number is not already in the sequence, otherwise a(n) = 3*a(n-1).

Terms

    a(0) =1a(1) =3a(2) =9a(3) =27a(4) =5a(5) =2a(6) =6a(7) =18a(8) =4a(9) =12a(10) =36a(11) =108a(12) =10a(13) =30a(14) =90a(15) =270a(16) =16a(17) =48a(18) =144a(19) =432a(20) =20a(21) =60a(22) =7a(23) =21a(24) =63a(25) =189a(26) =13a(27) =39a(28) =117a(29) =351

External references