|
| |
|
|
A068128
|
|
Triangular numbers with sum of digits = 6.
|
|
6
| |
|
|
6, 15, 105, 231, 2211, 3003, 20301, 112101, 2003001, 122000010, 200030001, 20000300001, 2000003000001, 200000030000001
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
COMMENTS
| 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.
|
|
|
CROSSREFS
| Cf. A068127.
Sequence in context: A194265 A129521 A029765 * A013222 A013228 A133472
Adjacent sequences: A068125 A068126 A068127 * A068129 A068130 A068131
|
|
|
KEYWORD
| base,easy,nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 21 2002
|
|
|
EXTENSIONS
| More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 06 2002
|
| |
|
|
