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Numbers k such that A007954(k) divides k and k divides A007954(k)^2.
3

%I #16 Aug 24 2021 10:14:57

%S 1,2,3,4,5,6,7,8,9,36,128,175,384,735,1296,2916,18432,34992,82944,

%T 139968,442368,2333772,4128768,9289728,12192768,13226976,13395375,

%U 13436928,27869184,49787136,376233984,429981696,1269789696,2633637888,4161798144,16728477696,19999187712,41479796736,72236924928

%N Numbers k such that A007954(k) divides k and k divides A007954(k)^2.

%C There are 66 terms below 10^400 with the largest containing 46 digits.

%H Max Alekseyev, <a href="/A257554/b257554.txt">Table of n, a(n) for n = 1..66</a>

%o (PARI) for(n=1,10^6, d=digits(n); p=prod(i=1,#d,d[i]); if(p && n%p==0 && p^2%n==0, print1(n,", ") )) \\ _Derek Orr_, Apr 29 2015

%Y Intersection of A007602 and A128606.

%K nonn,base

%O 1,2

%A _Max Alekseyev_, Apr 29 2015