cp's OEIS Frontend

A051540 Least common multiple of {2, 5, 8, 11, 14, ..., 3n+2} (A016789).

%I A051540 #35 Oct 27 2023 22:00:44
%S A051540 2,10,40,440,3080,52360,52360,1204280,15655640,454013560,1816054240,
%T A051540 1816054240,34505030560,1414706252960,1414706252960,66491193889120,
%U A051540 332455969445600,17620166380616800,17620166380616800
%N A051540 Least common multiple of {2, 5, 8, 11, 14, ..., 3n+2} (A016789).
%C A051540 Denominator of H(n,3,2), a generalized harmonic number. See A075135.
%H A051540 Robert Israel, <a href="/A051540/b051540.txt">Table of n, a(n) for n = 0..1026</a> (first 100 terms from Vincenzo Librandi)
%e A051540 a(3) = lcm{2, 5, 8, 11} = 440.
%p A051540 A[0]:= 2:
%p A051540 for n from 1 to 60 do A[n]:= ilcm(A[n-1],3*n+2) od:
%p A051540 seq(A[n],n=0..60); # _Robert Israel_, Apr 10 2018
%t A051540 Table[ Denominator[ Sum[1/i, {i, 2/3, n}]], {n, 1, 20}]
%t A051540 Table[ Apply[ LCM, Join[{1}, Table[2 + 3i, {i, 0, n}]]], {n, 0, 19}]
%o A051540 (Magma) k:=56; [Lcm([h: h in [2..j by 3]]): j in [2..k by 3]];  // _Bruno Berselli_, May 03 2011
%o A051540 (PARI) a(n) = lcm(vector(n+1, k, 3*k-1)); \\ _Michel Marcus_, Apr 10 2018
%o A051540 (GAP) List([0..20],n->Lcm(List([0..n],k->3*k+2))); # _Muniru A Asiru_, Apr 14 2018
%Y A051540 Cf. A016789, A051552. The numerators are in A074597.
%Y A051540 Cf. A075135.
%Y A051540 Cf. A051536.
%K A051540 easy,frac,nonn
%O A051540 0,1
%A A051540 _Asher Auel_
%E A051540 Edited by _Robert G. Wilson v_, Aug 27 2002
%E A051540 Offset corrected by _Robert Israel_, Apr 10 2018