Duplicate of A022801.

Terms

a(0) =3a(1) =8a(2) =10a(3) =15a(4) =20a(5) =28a(6) =41a(7) =60a(8) =90a(9) =138a(10) =215a(11) =339a(12) =540a(13) =863a(14) =1385a(15) =2229a(16) =3594a(17) =5802