A070304 a(n) = number of times n^2*k^2/(n^2+k^2) is an integer as k ranges over 0, 1, 2, ...

1, 2, 1, 2, 2, 2, 1, 2, 1, 6, 1, 2, 1, 2, 3, 2, 2, 2, 1, 7, 1, 2, 1, 2, 2, 4, 1, 2, 1, 8, 1, 2, 1, 3, 2, 2, 2, 2, 2, 7, 1, 2, 1, 2, 3, 2, 1, 2, 1, 7, 2, 4, 1, 2, 2, 2, 1, 4, 1, 9, 1, 2, 1, 2, 5, 2, 1, 4, 1, 7, 1, 2, 1, 3, 3, 2, 1, 5, 1, 7, 1, 3, 1, 2, 4, 2, 1, 2, 1, 8, 1, 2, 1, 2, 2, 2, 1, 2, 1, 8, 2, 4, 1, 4, 3

Offset: 1

Author

Benoit Cloitre, May 10 2002

Keywords

• easy
• nonn

Comments

A018892(n) gives the number of integers of the form nk/(n+k).

Crossrefs

Cf. A066451.

Programs

PARI

for(n=1,150,print1(sum(i=0,n^2,if((n^2*i^2)%(n^2+i^2),0,1)),","))