a(1) = 1; a(n+1) = floor(sqrt(Sum_{k=1..n} a(k)^2)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =4a(8) =6a(9) =8a(10) =11a(11) =16a(12) =22a(13) =31a(14) =44a(15) =62a(16) =87a(17) =123a(18) =174a(19) =246a(20) =348a(21) =492a(22) =695a(23) =983a(24) =1390a(25) =1966a(26) =2780a(27) =3931a(28) =5559a(29) =7862