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A081528
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n*LCM{1,2,...,n}.
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4
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1, 4, 18, 48, 300, 360, 2940, 6720, 22680, 25200, 304920, 332640, 4684680, 5045040, 5405400, 11531520, 208288080, 220540320, 4423058640, 4655851200, 4888643760, 5121436320, 123147264240, 128501493120, 669278610000, 696049754400
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Denominators in binomial transform of 1/(n+1)^2 - Paul Barry (pbarry(AT)wit.ie), Aug 06 2004
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 (rshepherd2(AT)hotmail.com), Aug 21 2006
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FORMULA
| Also equal to A003418(n) * n. - Martin Fuller (martin_n_fuller(AT)btinternet.com), Jan 03 2006
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PROG
| (DERIVE) a(n) := (n + 1)*LCM(VECTOR(k + 1, k, 0, n))
(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 (rshepherd2(AT)hotmail.com), Aug 21 2006
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CROSSREFS
| Cf. A027612, A027611, A022819, A002944, A081530, A097344.
Sequence in context: A073991 A052642 A102928 * A056147 A181857 A180805
Adjacent sequences: A081525 A081526 A081527 * A081529 A081530 A081531
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 27 2003
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EXTENSIONS
| More terms from Paul Barry (pbarry(AT)wit.ie), Aug 06 2004
Entry revised by N. J. A. Sloane (njas(AT)research.att.com), Jan 15 2006
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