Diagonal sums of triangle A191490.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =7a(5) =14a(6) =35a(7) =86a(8) =235a(9) =660a(10) =1968a(11) =6078a(12) =19570a(13) =65129a(14) =224057a(15) =793794a(16) =2892656a(17) =10819274a(18) =41480851a(19) =162783153a(20) =653115031a(21) =2676107761a(22) =11187573667a(23) =47675621875a(24) =206936072980a(25) =914179405191