Diagonal sums of number triangle A107027.

Terms

a(0) =1a(1) =1a(2) =3a(3) =3a(4) =5a(5) =7a(6) =11a(7) =19a(8) =35a(9) =69a(10) =151a(11) =339a(12) =829a(13) =2111a(14) =5607a(15) =15737a(16) =45289a(17) =136477a(18) =423279a(19) =1353671a(20) =4471673a(21) =15114479a(22) =52605755a(23) =187162155a(24) =681817179a(25) =2539492249a(26) =9646349779a(27) =37415172217a(28) =147745308403a(29) =594368656811