Triangle related to A001700 and A000302 (powers of 4).

Terms

a(0) =1a(1) =3a(2) =1a(3) =10a(4) =7a(5) =1a(6) =35a(7) =38a(8) =11a(9) =1a(10) =126a(11) =187a(12) =82a(13) =15a(14) =1a(15) =462a(16) =874a(17) =515a(18) =142a(19) =19a(20) =1a(21) =1716a(22) =3958a(23) =2934a(24) =1083a(25) =218a(26) =23a(27) =1a(28) =6435a(29) =17548