A068642 Index of the smallest n-digit palindromic triangular number, or 0 if no such number exists.

1, 10, 18, 77, 173, 1111, 1593, 8382, 18906, 50281, 167053, 0, 1620621, 6307938, 15126258, 50008881, 149142458, 846122222, 2480116437, 5513600773, 14667896198, 49786655918, 246644446642, 529670494286, 2466444446642

Offset: 1

Author

Amarnath Murthy, Feb 28 2002

Keywords

• base
• nonn

Examples

			a(4) = 77 as 77*78/2 = 3003 is the smallest 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, A068643, A068644, A000217, A003098, A008509, A008510, A054263.

Extensions

Edited by Patrick De Geest, Mar 24 2002