Triangular numbers which are the sum of distinct double factorials (A006882).

Terms

a(0) =1a(1) =3a(2) =6a(3) =10a(4) =15a(5) =21a(6) =28a(7) =66a(8) =105a(9) =120a(10) =153a(11) =171a(12) =435a(13) =561a(14) =946a(15) =1378a(16) =1485a(17) =3916a(18) =4005a(19) =4278a(20) =4851a(21) =4950a(22) =11781a(23) =14365a(24) =15576a(25) =47586a(26) =50086a(27) =51360a(28) =57970a(29) =60378