A079553 a(n) = floor( d(n^2) / d(n) ), where d() = A000005.

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, 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, 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

Offset: 1

Author

N. J. A. Sloane, Jan 24 2003

Keywords

• nonn

Comments

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

Differs from A001221 at n=1, 144, 180, 210, 216 etc. - R. J. Mathar, Sep 19 2008

References

• D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 41.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Programs

Mathematica

Table[Floor[DivisorSigma[0, n^2]/DivisorSigma[0, n]], {n, 1, 50}] (* G. C. Greubel, May 14 2017 *)

PARI

A079553(n)=floor(numdiv(n^2)/numdiv(n))