Diagonal sums of number triangle A176331.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =21a(6) =51a(7) =124a(8) =305a(9) =755a(10) =1879a(11) =4698a(12) =11792a(13) =29694a(14) =74984a(15) =189811a(16) =481498a(17) =1223713a(18) =3115200a(19) =7942134a(20) =20275362a(21) =51823246a(22) =132604193a(23) =339644739a(24) =870745187a(25) =2234208932a(26) =5737129623a(27) =14742751524a(28) =37909928908a(29) =97543380598