Diagonal of the triangle A354700.

Terms

a(0) =0a(1) =0a(2) =5a(3) =21a(4) =71a(5) =181a(6) =366a(7) =585a(8) =1009a(9) =1562a(10) =2312a(11) =3206a(12) =4490a(13) =5967a(14) =7939a(15) =10023a(16) =12913a(17) =15900a(18) =19951a(19) =24153a(20) =29483a(21) =35227a(22) =42039a(23) =49103a(24) =57998a(25) =67518a(26) =78426a(27) =90010a(28) =103631a(29) =117759