a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 7.

Terms

a(0) =127a(1) =8001a(2) =46228a(3) =256032a(4) =496062a(5) =2912364a(6) =2490216a(7) =8193024a(8) =11233404a(9) =31251906a(10) =22498812a(11) =93195648a(12) =51083718a(13) =156883608a(14) =180566568a(15) =262176768a(16) =191591946a(17) =707704452a(18) =331934820a(19) =1000060992a(20) =906438624a(21) =1417425156a(22) =854570808a(23) =2982260736a(24) =1550193750a(25) =3218274234