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A051539
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a(n) is the least common multiple of {1, 5, 9, 13, 17, ..., 4n+1} (A016813).
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8
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1, 5, 45, 585, 9945, 69615, 348075, 10094175, 111035925, 4108329225, 168441498225, 168441498225, 1179090487575, 62491795841475, 1187344120988025, 72427991380269525, 72427991380269525, 1665843801746199075, 121606597527472532475, 121606597527472532475
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OFFSET
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0,2
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COMMENTS
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This sequence coincides with sequence A097328 of denominators of 1 + 1/5 + 1/9 + 1/13 + ... + 1/(4n+1) iff n < 12. - T. D. Noe, Aug 04 2004
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LINKS
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EXAMPLE
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a(3) = LCM {1, 5, 9, 13} = 585.
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MATHEMATICA
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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 *)
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PROG
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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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CROSSREFS
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KEYWORD
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easy,nice,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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