A083907 - OEIS

A083907

a(1) = 1; for n>1, a(n) = n*a(n-1) if GCD(n,a(n-1)) = 1 else a(n) = a(n-1).

1, 2, 6, 6, 30, 30, 210, 210, 210, 210, 2310, 2310, 30030, 30030, 30030, 30030, 510510, 510510, 9699690, 9699690, 9699690, 9699690, 223092870, 223092870, 223092870, 223092870, 223092870, 223092870, 6469693230, 6469693230, 200560490130, 200560490130

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..32.

MAPLE

a:=[1];

L:=1;

for n from 2 to 50 do

if igcd(n, L)=1 then L:=n*L; fi;

a:=[op(a), L];

od:

a; # - N. J. A. Sloane, Sep 15 2021

MATHEMATICA

nxt[{n_, a_}]:={n+1, If[GCD[n+1, a]==1, a(n+1), a]}; NestList[nxt, {1, 1}, 40][[All, 2]] (* Harvey P. Dale, Sep 16 2021 *)

CROSSREFS

Sequence in context: A090549 A080326 A034386 * A084343 A025552 A284008

Adjacent sequences: A083904 A083905 A083906 * A083908 A083909 A083910

KEYWORD

nonn

AUTHOR

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 19 2003

EXTENSIONS

Corrected and extended by Harvey P. Dale, Sep 16 2021

STATUS

approved