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Search: id:A068128
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| A068128 |
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Triangular numbers with sum of digits = 6. |
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+0
7
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| 6, 15, 105, 231, 2211, 3003, 20301, 112101, 2003001, 122000010, 200030001, 20000300001, 2000003000001, 200000030000001
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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1. The sequence is unbounded, as the (2*10^k +1)-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
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Cf. A068127.
Adjacent sequences: A068125 A068126 A068127 this_sequence A068129 A068130 A068131
Sequence in context: A138547 A129521 A029765 this_sequence A013222 A013228 A133472
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KEYWORD
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base,easy,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 21 2002
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EXTENSIONS
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More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 06 2002
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