Diagonal of triangle A081994.

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =23a(5) =37a(6) =59a(7) =73a(8) =101a(9) =131a(10) =163a(11) =199a(12) =241a(13) =293a(14) =349a(15) =401a(16) =457a(17) =523a(18) =599a(19) =661a(20) =757a(21) =713a(22) =851a(23) =1049a(24) =1153a(25) =1277a(26) =1381a(27) =1499a(28) =1621a(29) =1777