First differences of triangular numbers with square pyramidal indices.

Terms

a(0) =1a(1) =14a(2) =90a(3) =360a(4) =1075a(5) =2646a(6) =5684a(7) =11040a(8) =19845a(9) =33550a(10) =53966a(11) =83304a(12) =124215a(13) =179830a(14) =253800a(15) =350336a(16) =474249a(17) =630990a(18) =826690a(19) =1068200a(20) =1363131a(21) =1719894a(22) =2147740a(23) =2656800a(24) =3258125a(25) =3963726a(26) =4786614a(27) =5740840a(28) =6841535a(29) =8104950