|
Search: id:A129120
|
|
|
| A129120 |
|
Undulating Harshad numbers: numbers divisible by the sum of their own digits with decimal expansions in an abab...ab pattern. |
|
+0
1
|
|
| 10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 70, 72, 80, 81, 84, 90, 171, 252, 414, 828, 1010, 1212, 1818, 2020, 2424, 3030, 3636, 4040, 4848, 5050, 5454, 6060, 7070, 7272, 8080, 9090, 10101, 13131, 20202, 23232, 26262, 30303, 39393
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
This definition of "undulating" is more restrictive than the one used in A033619 and excludes single-digit numbers and numbers of the pattern aaaaaa. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 15 2007
|
|
REFERENCES
|
J. Earls, Red Zen, Lulu Press, NY, 2006, pp. 56-57. ISBN: 978-1-4303-2017-3.
|
|
CROSSREFS
|
Cf. A005349, A003619.
Adjacent sequences: A129117 A129118 A129119 this_sequence A129121 A129122 A129123
Sequence in context: A109604 A063096 A031183 this_sequence A134516 A051247 A050579
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
Jason Earls (zevi_35711(AT)yahoo.com), May 25 2007
|
|
EXTENSIONS
|
More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 15 2007
|
|
|
Search completed in 0.002 seconds
|
