Partial sums of floor(5^n/7).

Terms

a(0) =0a(1) =3a(2) =20a(3) =109a(4) =555a(5) =2787a(6) =13947a(7) =69750a(8) =348767a(9) =1743856a(10) =8719302a(11) =43596534a(12) =217982694a(13) =1089913497a(14) =5449567514a(15) =27247837603a(16) =136239188049a(17) =681195940281