A077139 - OEIS

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

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

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

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 *)

CROSSREFS

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

Sequence in context: A055204 A212397 A008339 * A068629 A144361 A366369

Adjacent sequences: A077136 A077137 A077138 * A077140 A077141 A077142

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Oct 30 2002

EXTENSIONS

Corrected and extended by Ryan Propper, Jun 19 2005

STATUS

approved