Numbers of triples {x, y, z} such that z >= y > 1 and prime(x) + prime(y) * prime(z) = 2^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =4a(6) =5a(7) =15a(8) =22a(9) =43a(10) =65a(11) =131a(12) =204a(13) =387a(14) =635a(15) =1136a(16) =2048a(17) =3727a(18) =6794a(19) =12296a(20) =22601a(21) =41746a(22) =76778a(23) =141923a(24) =263414a(25) =491925a(26) =917269a(27) =1718985a(28) =3225496a(29) =6067030