A131940 Least common multiple of {1, 7, 13, 19, 25, ..., (6n+1)} (A016921).

1, 7, 91, 1729, 43225, 1339975, 49579075, 2131900225, 14923301575, 164156317325, 10013535356825, 670906868907275, 48976201430231075, 3869119912988254925, 65775038520800333725, 65775038520800333725, 6380178736517632371325

Offset: 0

Author

Jonathan Vos Post, Oct 05 2007

Keywords

• easy
• nonn

Comments

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).

Crossrefs

Cf. A008542, A016813, A016921, A051539.

Programs

Mathematica

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 *)
Join[{1},Table[LCM@@(6*Range[0,n]+1),{n,20}]] (* Harvey P. Dale, Apr 30 2019 *)

Extensions

More terms from Stefan Steinerberger, Oct 07 2007