This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A079553 #13 May 16 2020 09:49:08 %S A079553 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 A079553 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 A079553 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 A079553 a(n) = floor( d(n^2) / d(n) ), where d() = A000005. %C A079553 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 A079553 Differs from A001221 at n=1, 144, 180, 210, 216 etc. - _R. J. Mathar_, Sep 19 2008 %D A079553 D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 41. %H A079553 G. C. Greubel, <a href="/A079553/b079553.txt">Table of n, a(n) for n = 1..5000</a> %t A079553 Table[Floor[DivisorSigma[0, n^2]/DivisorSigma[0, n]], {n, 1, 50}] (* _G. C. Greubel_, May 14 2017 *) %o A079553 (PARI) A079553(n)=floor(numdiv(n^2)/numdiv(n)) %K A079553 nonn %O A079553 1,6 %A A079553 _N. J. A. Sloane_, Jan 24 2003