Triangular number index of A077206(n).

Terms

a(0) =1a(1) =5a(2) =32a(3) =126a(4) =141a(5) =447a(6) =4001a(7) =4472a(8) =40001a(9) =44721a(10) =141421a(11) =447214a(12) =3162278a(13) =4472136a(14) =34641016a(15) =109544512a(16) =400000001a(17) =447213596a(18) =3464101616a(19) =10954451150a(20) =31622776602a(21) =77459666925a(22) =316227766017a(23) =774596669241