A258781 - OEIS

%I #19 Nov 23 2015 01:25:19

%S 2,24,24,240,240,504,504,504,504,504,504,65520,65520,65520,65520,

%T 65520,65520,65520,65520,65520,65520,65520,65520,131040,131040,131040,

%U 131040,131040,131040,171864,171864,171864,171864,171864,171864,138181680,138181680,138181680

%N a(n) is the greatest positive integer k such that lambda(k) <= n where lambda is the Carmichael lambda function (A002322).

%H Eric W. Weisstein's mathWorld, <a href="http://mathworld.wolfram.com/ CarmichaelFunction.html">Carmichael Function</a>

%e a(2)=24 because lambda(24) = 2 and 24 is the greatest number such that lambda(24) <= 2.

%p with(numtheory):

%p for n from 1 to 30 do:

%p   ii:=0:

%p    for k from 10^7 by -1 to 1 while(ii=0)do:

%p    if lambda(k)<=n

%p    then

%p    printf(`%d, `,k):ii:=1:

%p    else

%p    fi:

%p   od:

%p od:

%Y Cf. A002322, A253215.

%K nonn

%O 1,1

%A _Michel Lagneau_, Jun 10 2015

%E a(36)-a(38) corrected by _Seth A. Troisi_, Nov 22 2015