A068644 Index of the largest n-digit palindromic triangular number, or 0 if no such number exists.

3, 11, 36, 132, 363, 1287, 3548, 11088, 18906, 111111, 417972, 0, 3707883, 12812392, 37009916, 128127032, 368505751, 1014708805, 3567632391, 11151642876, 36657342048, 104561417190, 417898160427, 1325269593372

Offset: 1

Author

Amarnath Murthy, Feb 28 2002

Keywords

• base
• nonn

Examples

			a(4) = 132 as 132*133/2 = 8778 is the largest 4-digit palindromic triangular number.
a(12) = 0 as no 12-digit palindromic triangular number exists.
		

Links

• P. De Geest, Exhaustive list of Palindromic Triangulars

Crossrefs

Cf. A068641, A068642, A068643, A000217, A003098, A008509, A008510, A054263.

Extensions

Edited by Patrick De Geest, Mar 24 2002