Palindromic Triangular Numbers/Mistake 2

Source Work

1986: David Wells: Curious and Interesting Numbers:

The Dictionary

$828,828$

Mistake

The only triangular palindrome, apart from $55$, $66$ and $666$.

Correction

From Palindromic Triangular Numbers, it can be seen that the sequence of triangular numbers which are also palindromic begins:

$1, 3, 6, 55, 66, 171, 595, 666, 3003, 5995, 8778, 15 \, 051, 66 \, 066, 617 \, 716, 828 \, 828, 1 \, 269 \, 621, 1 \, 680 \, 861, 3 \, 544 \, 453, \ldots$

In David Wells: Curious and Interesting Numbers (2nd ed.), this statement has been removed, and replace by Palindromic Triangular Numbers with Palindromic Halves, which is what he may have been searching for here.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $828,828$