a(n) = floor( sqrt(2) * (3/2)^n ).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =7a(5) =10a(6) =16a(7) =24a(8) =36a(9) =54a(10) =81a(11) =122a(12) =183a(13) =275a(14) =412a(15) =619a(16) =928a(17) =1393a(18) =2090a(19) =3135a(20) =4702a(21) =7053a(22) =10580a(23) =15871a(24) =23807a(25) =35710a(26) =53565a(27) =80348a(28) =120523a(29) =180784