a(n) = round(sqrt(a(n-2)^2 + a(n-1)^2)) with a(0) = 1 and a(1) = 2.

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =8a(8) =10a(9) =13a(10) =16a(11) =21a(12) =26a(13) =33a(14) =42a(15) =53a(16) =68a(17) =86a(18) =110a(19) =140a(20) =178a(21) =226a(22) =288a(23) =366a(24) =466a(25) =593a(26) =754a(27) =959a(28) =1220a(29) =1552