a(n+3) = floor( ( a(n) + 2*a(n+1) + 3*a(n+2) )/4 ), with a(0), a(1), a(2) equal to 0, 1, 2.

Terms

a(0) =0a(1) =1a(2) =2a(3) =2a(4) =2a(5) =3a(6) =3a(7) =4a(8) =5a(9) =6a(10) =8a(11) =10a(12) =13a(13) =16a(14) =21a(15) =27a(16) =34a(17) =44a(18) =56a(19) =72a(20) =93a(21) =119a(22) =153a(23) =197a(24) =254a(25) =327a(26) =421a(27) =542a(28) =698a(29) =899