Diagonal sums of number triangle A108477.

Terms

a(0) =1a(1) =1a(2) =2a(3) =14a(4) =43a(5) =127a(6) =468a(7) =1596a(8) =5253a(9) =17917a(10) =60918a(11) =205194a(12) =694287a(13) =2351611a(14) =7951336a(15) =26894840a(16) =91004105a(17) =307854073a(18) =1041410602a(19) =3523170438a(20) =11918842803a(21) =40320750711a(22) =136404504124a(23) =461454010164