%I #7 Aug 11 2024 14:41:34

%S 6,66,666,8778,66066,828828,6295926,61477416,178727871,6172882716,

%T 87350505378,0,68742000024786,82078700787028,684866959668486,

%U 8208268228628028,67898244444289876,514816979979618415

%N Largest n-digit palindromic triangular number, or 0 if no such number exists.

%H P. De Geest, <a href="https://www.worldofnumbers.com/em_alltria.htm">Exhaustive list of Palindromic Triangulars</a>

%e a(4) = 8778 = 132*133/2 is the largest 4-digit palindromic triangular number.

%e a(12) = 0 as no 12-digit palindromic triangular number exists.

%Y Cf. A068641, A068642, A068644, A000217, A003098, A008509, A008510, A054263.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Feb 28 2002

%E Edited by _Patrick De Geest_, Mar 24 2002