

A068642


Index of the smallest ndigit palindromic triangular number. If no such number exists then 0.


3



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
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..25.
P. De Geest, Exhaustive list of Palindromic Triangulars


EXAMPLE

a(4) = 77 as 77*78/2 = 3003 is palindromic. a(12) = 0 as no 12 digit palindromic triangular exists.


CROSSREFS

Cf. A068641, A068643, A068644, A000217, A003098, A008509, A008510, A054263.
Sequence in context: A266708 A186235 A241053 * A198309 A167342 A288781
Adjacent sequences: A068639 A068640 A068641 * A068643 A068644 A068645


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Feb 28 2002


EXTENSIONS

Edited by Patrick De Geest, Mar 24 2002.


STATUS

approved



