The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A241475 Triangle t(n,r) = s(n,r)*s(n,r+1), where s(n,r) = lcm(n,n-1,...,n-r+1)/lcm(1,2,...,r-1,r), n >= 1 and 0 <= r < n. 0
 1, 2, 2, 3, 9, 3, 4, 24, 12, 2, 5, 50, 100, 50, 5, 6, 90, 150, 50, 5, 1, 7, 147, 735, 1225, 245, 49, 7, 8, 224, 784, 1960, 980, 196, 28, 2, 9, 324, 3024, 3528, 1764, 1764, 252, 18, 3, 10, 450, 2700, 12600, 8820, 1764, 252, 18, 3, 1, 11, 605, 9075, 54450, 152460, 213444, 30492, 2178, 363, 121, 11 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The first eight terms and the first two terms of every row are identical to those of A132812. LINKS S. M. Khairnar, Anant W. Vyawahare and J. N. Salunkhe, On Smarandache least common multiple ratio, Scientia Magna Vol. 5 (2009), No. 1, 29-36. Amarnath Murthy, Some Notions on Least Common Multiples, Smarandache Notions Journal, Vol. 12, No. 1-2-3, Spring 2001. EXAMPLE Triangle begins:   1;   2,  2;   3,  9,   3;   4, 24,  12,  2;   5, 50, 100, 50, 5;   6, 90, 150, 50, 5, 1;   ... MATHEMATICA s[_, 0] = 1; s[n_, r_?NumericQ] := LCM @@ Table[n-k+1, {k, 1, r}] / LCM @@ Table[k, {k, 1, r}]; t[n_, r_] := s[n, r]*s[n, r+1]; Table[t[n, r] , {n, 1, 12}, {r, 0, n-1}] // Flatten CROSSREFS Cf. A067049, A093430, A132812. Sequence in context: A153941 A184844 A252848 * A132812 A203371 A181206 Adjacent sequences:  A241472 A241473 A241474 * A241476 A241477 A241478 KEYWORD nonn,tabl AUTHOR Jean-François Alcover, Apr 23 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 23 08:56 EDT 2021. Contains 345395 sequences. (Running on oeis4.)