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A068130
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Triangular numbers with sum of digits = 15.
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3
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78, 276, 465, 528, 780, 861, 1176, 1275, 1653, 1770, 2346, 2850, 3570, 3741, 4371, 4560, 5253, 5460, 6216, 6441, 7260, 7503, 11175, 12246, 12561, 14028, 15225, 17205, 20706, 22155, 24090, 24531, 26106, 28203, 30381, 32640, 33153, 35511
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 1. The sequence is unbounded, as the (2*10^k +3)-th triangular number is a term. 2. The sum of the digits of triangular numbers in most cases is a triangular number. 3. Conjecture: For every triangular number T there exist infinitely many triangular numbers with sum of digits = T.
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CROSSREFS
| Cf. A068127, A068128, A068129.
Sequence in context: A119146 A044410 A044791 * A118938 A206004 A007255
Adjacent sequences: A068127 A068128 A068129 * A068131 A068132 A068133
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KEYWORD
| base,easy,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 21 2002
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EXTENSIONS
| More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 06 2002
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