a(n) = 2^n-n^6.

Terms

a(0) =1a(1) =1a(2) =-60a(3) =-721a(4) =-4080a(5) =-15593a(6) =-46592a(7) =-117521a(8) =-261888a(9) =-530929a(10) =-998976a(11) =-1769513a(12) =-2981888a(13) =-4818617a(14) =-7513152a(15) =-11357857a(16) =-16711680a(17) =-24006497a(18) =-33750080a(19) =-46521593a(20) =-62951424a(21) =-83668969a(22) =-109185600a(23) =-139647281a(24) =-174325760a(25) =-210586193a(26) =-241806912