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%I #8 Apr 30 2019 12:03:53
%S 1,7,91,1729,43225,1339975,49579075,2131900225,14923301575,
%T 164156317325,10013535356825,670906868907275,48976201430231075,
%U 3869119912988254925,65775038520800333725,65775038520800333725,6380178736517632371325
%N Least common multiple of {1, 7, 13, 19, 25, ..., (6n+1)} (A016921).
%C This is to 6n+1 (A016921) as A051539 is to 4n+1 (A016813). Because 6*9 + 1 = 49 is divisible by 6*1 + 1 = 7, this sequence differs from A008542. a(n) | A008542(n+1).
%t a = {1}; Do[l = 1; For[j = 1, j < n, j++, l = LCM[l, 6*j + 1]]; AppendTo[a, l], {n, 2, 20}]; a (* _Stefan Steinerberger_, Oct 07 2007 *)
%t Join[{1},Table[LCM@@(6*Range[0,n]+1),{n,20}]] (* _Harvey P. Dale_, Apr 30 2019 *)
%Y Cf. A008542, A016813, A016921, A051539.
%K easy,nonn
%O 0,2
%A _Jonathan Vos Post_, Oct 05 2007
%E More terms from _Stefan Steinerberger_, Oct 07 2007
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