|
| |
|
|
A093430
|
|
Triangle read by rows: T(n,k)=LCM(n,n-1,...,n-k+2,n-k+1)/LCM(1,2,...,k) (1<=k<=n).
|
|
2
| |
|
|
1, 2, 1, 3, 3, 1, 4, 6, 2, 1, 5, 10, 10, 5, 1, 6, 15, 10, 5, 1, 1, 7, 21, 35, 35, 7, 7, 1, 8, 28, 28, 70, 14, 14, 2, 1, 9, 36, 84, 42, 42, 42, 6, 3, 1, 10, 45, 60, 210, 42, 42, 6, 3, 1, 1, 11, 55, 165, 330, 462, 462, 66, 33, 11, 11, 1, 12, 66, 110, 165, 66, 462, 66, 33, 11, 11, 1, 1, 13
(list; table; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Bakir Farhi, p.7, gives the first 12 rows of the table. He seems not to realize that Amarnath Murthy published the same formula and table in 2004, as extended by Emeric Deutsch in 2006. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 09 2010]
|
|
|
LINKS
| Bakir Farhi, An analog of the arithmetic triangle obtained by replacing the products by the least common multiples , Feb 6, 2010. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 09 2010]
|
|
|
EXAMPLE
| T(7,3)=LCM(7,6,5)/LCM(1,2,3)=210/6=35.
|
|
|
MAPLE
| T:=(n, k)->lcm(seq(i, i=n-k+1..n))/lcm(seq(j, j=1..k)): for n from 1 to 13 do seq(T(n, k), k=1..n) od; # yields sequence in triangular form (Deutsch)
|
|
|
CROSSREFS
| Cf. A093431, A093432, A093433.
Row sums yield A093431.
Sequence in context: A073020 A090349 A157379 * A074659 A131251 A057145
Adjacent sequences: A093427 A093428 A093429 * A093431 A093432 A093433
|
|
|
KEYWORD
| nonn,tabl
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 31 2004
|
|
|
EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 30 2006
|
| |
|
|
