Triangular numbers with every digit a triangular number.

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =10a(5) =36a(6) =66a(7) =136a(8) =300a(9) =630a(10) =666a(11) =3003a(12) =3160a(13) =10011a(14) =13366a(15) =16110a(16) =60031a(17) =66066a(18) =106030a(19) =163306a(20) =303031a(21) =333336a(22) =336610a(23) =600060a(24) =630003a(25) =1010331a(26) =1030330a(27) =1063611a(28) =1313010a(29) =3306306