a(n) = 35*2^n + 5*4^n + 15*3^n + 5^n + 70.

Terms

a(0) =126a(1) =210a(2) =450a(3) =1200a(4) =3750a(5) =13080a(6) =49350a(7) =197400a(8) =825750a(9) =3577080a(10) =15930150a(11) =72528600a(12) =336141750a(13) =1580449080a(14) =7518010950a(15) =36102667800a(16) =174710721750a(17) =850780489080