A014851 - OEIS

%I #13 Jul 03 2021 16:13:13

%S 1,2,3,4,6,9,10,12,18,20,21,27,30,36,42,50,54,60,63,68,78,81,84,90,

%T 100,108,110,126,147,150,156,162,171,180,189,204,210,220,234,243,250,

%U 252,270,294,300,310,324,330,340,342,378,390,410,420,441,450,468,486

%N Numbers k that divide s(k), where s(1)=1, s(j)=4*s(j-1)+j.

%H Harvey P. Dale, <a href="/A014851/b014851.txt">Table of n, a(n) for n = 1..1000</a>

%t nxt[{k_,a_}]:={k+1,4a+k+1}; Transpose[Select[NestList[nxt,{1,1},500], Divisible[#[[2]],#[[1]]]&]][[1]] (* _Harvey P. Dale_, May 29 2013 *)

%Y s(n) = A014825(n).

%K nonn

%O 1,2

%A _N. J. A. Sloane_, _Olivier Gérard_