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A068644
Index of the largest n-digit palindromic triangular number, or 0 if no such number exists.
3
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
1,1
EXAMPLE
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.
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Feb 28 2002
EXTENSIONS
Edited by Patrick De Geest, Mar 24 2002
STATUS
approved