Partial sums of A050406.

Terms

a(0) =1a(1) =17a(2) =108a(3) =444a(4) =1410a(5) =3762a(6) =8844a(7) =18876a(8) =37323a(9) =69355a(10) =122408a(11) =206856a(12) =336804a(13) =531012a(14) =813960a(15) =1217064a(16) =1780053a(17) =2552517a(18) =3595636a(19) =4984100a(20) =6808230a(21) =9176310a(22) =12217140a(23) =16082820a(24) =20951775