Sum of binomial(n,k) over squarefree k.

Terms

a(0) =1a(1) =3a(2) =7a(3) =14a(4) =26a(5) =48a(6) =92a(7) =184a(8) =375a(9) =758a(10) =1497a(11) =2884a(12) =5461a(13) =10286a(14) =19507a(15) =37584a(16) =73866a(17) =147987a(18) =301075a(19) =618794a(20) =1278116a(21) =2640993a(22) =5439593a(23) =11138764a(24) =22640100a(25) =45644797a(26) =91293390a(27) =181301470a(28) =358024924a(29) =704359427