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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A067049 Triangle T(n,r) = lcm(n,n-1,n-2,...,n-r+1)/lcm(1,2,3,...,r-1,r), 0 <= r < n. 3
 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 2, 1, 1, 5, 10, 10, 5, 1, 1, 6, 15, 10, 5, 1, 1, 1, 7, 21, 35, 35, 7, 7, 1, 1, 8, 28, 28, 70, 14, 14, 2, 1, 1, 9, 36, 84, 42, 42, 42, 6, 3, 1, 1, 10, 45, 60, 210, 42, 42, 6, 3, 1, 1, 1, 11, 55, 165, 330, 462, 462, 66, 33, 11, 11, 1, 1, 12, 66, 110 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 REFERENCES Amarnath Murthy, Some Notions on Least Common Multiples, Smarandache Notions Journal, Vol. 12, No. 1-2-3, Spring 2001. LINKS EXAMPLE Triangle begins:   1;   1, 1;   1, 2, 1;   1, 3, 3, 1;   1, 4, 6, 2, 1; ... MATHEMATICA t[n_, r_] :=  LCM @@ Table[n-k+1, {k, 1, r}] / LCM @@ Table[k, {k, 1, r}]; t[_, 0] = 1; Table[t[n, r], {n, 0, 12}, {r, 0, n}] // Flatten (* Jean-François Alcover, Apr 22 2014 *) PROG (PARI) t(n, r) = {nt = 1; for (k = n-r+1, n, nt = lcm(nt, k); ); dt = 1; for (k = 1, r, dt = lcm(dt, k); ); return (nt/dt); } \\ Michel Marcus, Sep 14 2013 CROSSREFS Diagonals give A067046, A067047, A067048. Row sums give A061297. Sequence in context: A046688 A208342 A157283 * A090641 A055216 A216236 Adjacent sequences:  A067046 A067047 A067048 * A067050 A067051 A067052 KEYWORD nonn,tabl AUTHOR Amarnath Murthy, Dec 30 2001 EXTENSIONS More terms from Vladeta Jovovic, Dec 31 2001 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 November 30 19:02 EST 2021. Contains 349424 sequences. (Running on oeis4.)