Perimeter (rounded down) of a tetraflake-like fractal after n iterations, a(1) = 1 (see comments).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =7a(6) =10a(7) =16a(8) =25a(9) =39a(10) =61a(11) =97a(12) =155a(13) =249a(14) =404a(15) =657a(16) =1073a(17) =1759a(18) =2892a(19) =4768a(20) =7877a(21) =13036a(22) =21602a(23) =35838a(24) =59508a(25) =98885a(26) =164416a(27) =273502a(28) =455137a(29) =757628