%I #7 Sep 19 2024 21:59:31
%S 0,1,3,6,10,15,21,28,36,45,55,66,78,91,105,231,435,465,666,1035,2211,
%T 3916,4005,6216,6786,19900,41905,46665,48205,162165,171405,200661,
%U 222111,329266,400065,1057785,1646205,2003001,2318781,2943951,10628355
%N Triangular numbers whose external digits as well as internal digits form triangular numbers.
%C Intersection of A077366 and A077367.
%Y Cf. A077366, A077367.
%K base,easy,nonn
%O 1,3
%A _Amarnath Murthy_, Nov 06 2002
%E Extended by _Ray Chandler_, Feb 28 2007
%E Offset changed by _Andrew Howroyd_, Sep 19 2024