|
%I #13 May 16 2020 09:49:08
%S 1,1,1,1,1,2,1,1,1,2,1,2,1,2,2,1,1,2,1,2,2,2,1,2,1,2,1,2,1,3,1,1,2,2,
%T 2,2,1,2,2,2,1,3,1,2,2,2,1,2,1,2,2,2,1,2,2,2,2,2,1,3,1,2,2,1,2,3,1,2,
%U 2,3,1,2,1,2,2,2,2,3,1,2,1,2,1,3,2,2,2,2,1,3,2,2,2,2,2,2,1,2,2,2,1,3,1,2,3
%N a(n) = floor( d(n^2) / d(n) ), where d() = A000005.
%C This sequence and A087802 first differ at term 144: a(144)=3 and A087802(144)=2. This sequence and A064372 first differ at term 64: a(64)=1 and A064372(64)=2. The next difference doesn't appear until a(144)=3 and A064372(144)=2. - _Rick L. Shepherd_, Mar 07 2004
%C Differs from A001221 at n=1, 144, 180, 210, 216 etc. - _R. J. Mathar_, Sep 19 2008
%D D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 41.
%H G. C. Greubel, <a href="/A079553/b079553.txt">Table of n, a(n) for n = 1..5000</a>
%t Table[Floor[DivisorSigma[0, n^2]/DivisorSigma[0, n]], {n, 1, 50}] (* _G. C. Greubel_, May 14 2017 *)
%o (PARI) A079553(n)=floor(numdiv(n^2)/numdiv(n))
%K nonn
%O 1,6
%A _N. J. A. Sloane_, Jan 24 2003
|
