Numbers that are simultaneously k-gonal and k-gonal pyramidal for some k >= 3.

Terms

a(0) =0a(1) =1a(2) =10a(3) =120a(4) =175a(5) =441a(6) =946a(7) =1045a(8) =1540a(9) =4900a(10) =5985a(11) =7140a(12) =23001a(13) =23725a(14) =48280a(15) =195661a(16) =245905a(17) =314755a(18) =801801a(19) =975061a(20) =1169686a(21) =3578401a(22) =10680265a(23) =27453385a(24) =55202400a(25) =63016921a(26) =101337426a(27) =132361021a(28) =197427385a(29) =258815701