A051539 a(n) is the least common multiple of {1, 5, 9, 13, 17, ..., 4n+1} (A016813).
1, 5, 45, 585, 9945, 69615, 348075, 10094175, 111035925, 4108329225, 168441498225, 168441498225, 1179090487575, 62491795841475, 1187344120988025, 72427991380269525, 72427991380269525, 1665843801746199075, 121606597527472532475, 121606597527472532475
Offset: 0
Examples
a(3) = LCM {1, 5, 9, 13} = 585.
Links
- Harvey P. Dale, Table of n, a(n) for n = 0..866 (first 201 terms from T. D. Noe)
- Index entries for sequences related to lcm's
Programs
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Magma
k:=77; [Lcm([h: h in [1..j by 4]]): j in [1..k by 4]]; // Bruno Berselli, May 03 2011
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Mathematica
Table[ Apply[ LCM, Join[{1}, Table[1 + 4i, {i, 0, n}]]], {n, 0, 19}] nn=20;Table[LCM@@Take[4Range[0,nn-1]+1,n],{n,nn}] (* Harvey P. Dale, Jul 04 2011 *) Table[LCM@@NestList[#+4&,1,n],{n,0,20}] (* Harvey P. Dale, Nov 21 2016 *) -
PARI
a(n)=lcm(vector(n,i,4*n+1)) \\ Charles R Greathouse IV, Feb 09 2017
Extensions
Edited by Robert G. Wilson v, Aug 27 2002
a(16) corrected by T. D. Noe, Feb 08 2008
Comments