A symmetric number triangle based on 2^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =13a(5) =1a(6) =1a(7) =41a(8) =41a(9) =1a(10) =1a(11) =85a(12) =321a(13) =85a(14) =1a(15) =1a(16) =145a(17) =1289a(18) =1289a(19) =145a(20) =1a(21) =1a(22) =221a(23) =3649a(24) =8989a(25) =3649a(26) =221a(27) =1a(28) =1a(29) =313