Shifts 2 places left when convolved with itself.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =11a(7) =22a(8) =44a(9) =90a(10) =187a(11) =392a(12) =832a(13) =1778a(14) =3831a(15) =8304a(16) =18104a(17) =39666a(18) =87296a(19) =192896a(20) =427778a(21) =951808a(22) =2124135a(23) =4753476a(24) =10664458a(25) =23981698a(26) =54045448a(27) =122041844a(28) =276101386a(29) =625725936