A077139 a(1) = 1, a(n) = lcm(n, a(n-1)) / gcd(n, a(n-1)).

1, 2, 6, 6, 30, 5, 35, 280, 2520, 252, 2772, 231, 3003, 858, 1430, 5720, 97240, 437580, 8314020, 415701, 969969, 176358, 4056234, 2704156, 67603900, 2600150, 70204050, 10029150, 290845350, 9694845, 300540195, 9617286240, 35263382880, 1037158320

Offset: 1

Author

Amarnath Murthy, Oct 30 2002

Keywords

• nonn

Examples

			a(5) = 30 because given a(4) = 6: lcm(5, 6) / gcd(5, 6) = 30 / 1 = 30.
		

Crossrefs

Essentially a duplicate of A008339, which is the main entry for this sequence.

Programs

Mathematica

k = 1; Print[k]; Do[k = LCM[n, k] / GCD[n, k]; Print[k], {n, 2, 30}] (* Ryan Propper, Jun 19 2005 *)
nxt[{n_,a_}]:={n+1,LCM[n+1,a]/GCD[n+1,a]}; Transpose[NestList[nxt,{1,1},40]] [[2]] (* Harvey P. Dale, Mar 07 2013 *)

Extensions

Corrected and extended by Ryan Propper, Jun 19 2005