%I

%S 1,3,5,7,15,21,25,35,75,105,125,175,301,375,525,625,875,903,1389,1505,

%T 1875,2625,3125,3165,4375,4417,4515,6945,7525,9375,9723,11325,12943,

%U 13125,13251,15625,15825,21875,22085,22155,22575,23233,31375

%N Numbers n such that n divides s(n), where s(1)=1, s(k)=21*s(k-1)+k.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, _Olivier GĂ©rard_