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A051536
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Least common multiple of {1, 4, 7, 10, 13 ...,(3n+1)} (A016777).
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6
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1, 4, 28, 140, 1820, 7280, 138320, 1521520, 7607600, 7607600, 235835600, 4009205200, 148340592400, 148340592400, 6378645473200, 146708845883600, 1026961921185200, 1026961921185200, 1026961921185200, 29781895714370800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| This sequence coincides with the sequence of denominators of 1+1/4+1/7+1/10+...+1/3n+1 for n<29. - T. D. Noe (noe(AT)sspectra.com), Aug 04 2004
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LINKS
| T. D. Noe, Table of n, a(n) for n=0..200
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EXAMPLE
| a(4) = lcm of {1, 4, 7, 10, 13} = 1820
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MATHEMATICA
| Table[ Denominator[ Sum[1/i, {i, 1/3, n}]], {n, 1, 20}]
Table[ Apply[ LCM, Join[{1}, Table[1 + 3i, {i, 0, n}]]], {n, 0, 19}]
Table[Denominator[Total[1/Range[1, 3n+1, 3]]], {n, 0, 29}]
With[{nn=30, lst=3*Range[0, nn]+1}, Table[LCM@@Take[lst, n], {n, nn}]] (* From Harvey P. Dale, Jul 20 2011 *)
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PROG
| (MAGMA) k:=58; [Lcm([h: h in [1..j by 3]]): j in [1..k by 3]]; // Bruno Berselli, May 03 2011
(Haskell)
a051536 n = foldl lcm 1 $ take n a016777_list
-- Reinhard Zumkeller, Feb 10 2012
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CROSSREFS
| The numerators are in A074596.
Cf. A075135, A059457.
Cf. A051540.
Sequence in context: A131459 A139736 A128941 * A043013 A145544 A006302
Adjacent sequences: A051533 A051534 A051535 * A051537 A051538 A051539
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KEYWORD
| easy,frac,nice,nonn,changed
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AUTHOR
| Asher Auel (asher.auel(AT)reed.edu)
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EXTENSIONS
| Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 27 2002
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