Triangular numbers of the form 10*k.

Terms

a(0) =0a(1) =10a(2) =120a(3) =190a(4) =210a(5) =300a(6) =630a(7) =780a(8) =820a(9) =990a(10) =1540a(11) =1770a(12) =1830a(13) =2080a(14) =2850a(15) =3160a(16) =3240a(17) =3570a(18) =4560a(19) =4950a(20) =5050a(21) =5460a(22) =6670a(23) =7140a(24) =7260a(25) =7750a(26) =9180a(27) =9730a(28) =9870a(29) =10440