Triangle of coefficients in expansion of (1+4x)^n.

Terms

a(0) =1a(1) =1a(2) =4a(3) =1a(4) =8a(5) =16a(6) =1a(7) =12a(8) =48a(9) =64a(10) =1a(11) =16a(12) =96a(13) =256a(14) =256a(15) =1a(16) =20a(17) =160a(18) =640a(19) =1280a(20) =1024a(21) =1a(22) =24a(23) =240a(24) =1280a(25) =3840a(26) =6144a(27) =4096a(28) =1a(29) =28