a(n) = 531441*n^2 - 322218*n + 48842.

Terms

a(0) =258065a(1) =1530170a(2) =3865157a(3) =7263026a(4) =11723777a(5) =17247410a(6) =23833925a(7) =31483322a(8) =40195601a(9) =49970762a(10) =60808805a(11) =72709730a(12) =85673537a(13) =99700226a(14) =114789797a(15) =130942250a(16) =148157585a(17) =166435802a(18) =185776901a(19) =206180882a(20) =227647745a(21) =250177490