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A008509 Numbers n such that n-th triangular number is palindromic. +0
11
1, 2, 3, 10, 11, 18, 34, 36, 77, 109, 132, 173, 363, 1111, 1287, 1593, 1833, 2662, 3185, 3369, 3548, 8382, 11088, 18906, 50281, 57166, 102849, 111111, 167053, 179158, 246642, 337650, 342270, 365436, 417972, 1620621, 3240425, 3457634, 3707883 (list; graph; listen)
OFFSET

1,2

REFERENCES

Charles W. Trigg, Palindromic Triangular Numbers, J. Rec. Math., 6 (1973), 146-147.

D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, 93.

LINKS

P. De Geest, Palindromic Triangulars

CROSSREFS

Cf. A003098, A002113, A000217, A083571, A050721, A050722.

Sequence in context: A081706 A032804 A047473 this_sequence A081868 A092986 A006092

Adjacent sequences: A008506 A008507 A008508 this_sequence A008510 A008511 A008512

KEYWORD

nonn,base

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com)

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Last modified December 16 13:01 EST 2009. Contains 170825 sequences.


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