This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081528 #37 Jan 20 2024 11:26:59
%S A081528 1,4,18,48,300,360,2940,6720,22680,25200,304920,332640,4684680,
%T A081528 5045040,5405400,11531520,208288080,220540320,4423058640,4655851200,
%U A081528 4888643760,5121436320,123147264240,128501493120,669278610000,696049754400
%N A081528 a(n) = n*lcm{1,2,...,n}.
%C A081528 Denominators in binomial transform of 1/(n + 1)^2. - _Paul Barry_, Aug 06 2004
%C A081528 Construct a sequence S_n from n sequences b_1, b_2, ..., b_n of periods 1, 2, ..., n, respectively, say, b_1 = [1, 1, ...], b_2 = [1, 2, 1, 2, ...], ..., b_n = [1, 2, 3, ..., n, 1, 2, 3, ..., n, ...], by taking S_n = [b_1(1), b_2(1), ..., b_n(1), b_1(2), b_2(2), ..., b_n(2), ..., b_1(n), b_2(n), ..., b_n(n), ...] (by listing the b_i sequences in rows and taking each column in turn as the next n terms of S_n). Then a(n) is the period of sequence S_n. - _Rick L. Shepherd_, Aug 21 2006
%C A081528 This is a sequence that goes in strictly ascending order. The related sequence A003418 also goes in ascending order but has consecutive repeated terms. Since n increases, then so too does a(n) even when A003418(n) doesn't. - _Alonso del Arte_, Nov 25 2012
%F A081528 a(n) = A003418(n) * n. - _Martin Fuller_, Jan 03 2006
%e A081528 a(2) = 4 because the least common multiple of 1 and 2 is 2, and 2 * 2 = 4.
%e A081528 a(3) = 18 because lcm(1,2,3) = 6, and 3 * 6 = 18.
%e A081528 a(4) = 48 because lcm(1, 2, 3, 4) = 12, and 4 * 12 = 48.
%t A081528 Table[n*LCM@@Range[n], {n, 30}] (* _Harvey P. Dale_, Oct 09 2012 *)
%o A081528 (Derive) a(n) := (n + 1)*LCM(VECTOR(k + 1, k, 0, n)) " Paul Barry, Aug 06 2004 "
%o A081528 (PARI) l=vector(35); l[1]=1; print1("1, "); for(n=2,35, l[n]=lcm(l[n-1],n); print1(n*l[n],", ")) \\ _Rick L. Shepherd_, Aug 21 2006
%Y A081528 Cf. A027612, A027611, A022819, A002944, A081530, A097344.
%K A081528 nonn,easy
%O A081528 1,2
%A A081528 _Amarnath Murthy_, Mar 27 2003
%E A081528 More terms from _Paul Barry_, Aug 06 2004
%E A081528 Entry revised by _N. J. A. Sloane_, Jan 15 2006