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A051173 Triangular array T read by rows: T(u,v) = lcm(u,v). 16
1, 2, 2, 3, 6, 3, 4, 4, 12, 4, 5, 10, 15, 20, 5, 6, 6, 6, 12, 30, 6, 7, 14, 21, 28, 35, 42, 7, 8, 8, 24, 8, 40, 24, 56, 8, 9, 18, 9, 36, 45, 18, 63, 72, 9, 10, 10, 30, 20, 10, 30, 70, 40, 90, 10, 11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 11, 12, 12, 12, 12, 60, 12, 84, 24, 36, 60, 132, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Keith Bourque and Steve Ligh, Matrices associated with multiplicative functions, Linear Algebra and its Applications 216 (1995) 267-275.
Shaofang Hong and Raphael Loewy, Asymptotic behavior of eigenvalues of greatest common divisor matrices, Glasgow Mathematical Journal, Vol. 46, No. 3 (2004) 551-569.
Eric Weisstein's World of Mathematics, Least Common Multiple
FORMULA
T(n,1) = T(n,n) = n. T(n,2) = A109043(n). - R. J. Mathar, Apr 07 2011
T(n,k) = A075362(n,k)/A050873(n,k), 1<=k<=n. - Reinhard Zumkeller, Apr 25 2011
T(n,k) = A051537(n,k) * A050873(n,k). - Reinhard Zumkeller, Jul 07 2013
EXAMPLE
Triangle begins:
1;
2, 2;
3, 6, 3;
4, 4, 12, 4;
5, 10, 15, 20, 5;
6, 6, 6, 12, 30, 6;
7, 14, 21, 28, 35, 42, 7;
8, 8, 24, 8, 40, 24, 56, 8;
MAPLE
A051173 := proc(u, v) ilcm(u, v) ; end proc: # R. J. Mathar, Apr 07 2011
MATHEMATICA
Table[LCM[n, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jan 30 2018 *)
PROG
(Haskell)
a051173 = lcm
a051173_row n = a051173_tabl !! (n-1)
a051173_tabl = map (\x -> map (lcm x) [1..x]) [1..]
-- Reinhard Zumkeller, Aug 13 2013, Jul 07 2013
(PARI) T(n, k) = lcm(n, k);
tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n, k), ", ")); print; ) \\ Michel Marcus, Jul 10 2017
CROSSREFS
Cf. A003990.
Cf. A051193 (row sums), A000384 (central terms).
Cf. A002260.
Sequence in context: A260389 A291372 A064426 * A322744 A128228 A190098
KEYWORD
nonn,easy,tabl
AUTHOR
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)