(1/8) times the sum of the elements of all subsets of [n] whose sum is divisible by eight.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =3a(6) =10a(7) =27a(8) =70a(9) =178a(10) =438a(11) =1056a(12) =2496a(13) =5824a(14) =13440a(15) =30720a(16) =69632a(17) =156672a(18) =350208a(19) =778240a(20) =1720320a(21) =3784704a(22) =8290304a(23) =18087936a(24) =39321600a(25) =85196800a(26) =184025088a(27) =396361728a(28) =851443712a(29) =1824522240