Number of subsets of the n-th roots of unity summing to a real number.

Terms

a(0) =2a(1) =4a(2) =4a(3) =8a(4) =8a(5) =24a(6) =16a(7) =48a(8) =40a(9) =144a(10) =64a(11) =336a(12) =128a(13) =864a(14) =416a(15) =1728a(16) =512a(17) =8304a(18) =1024a(19) =10656a(20) =4032a(21) =31104a(22) =4096a(23) =116256a(24) =9248a(25) =186624a(26) =40000a(27) =374976a(28) =32768a(29) =3537024