A066451 -id:A066451 - cp's OEIS frontend

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

Benoit Cloitre, May 10 2002

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

Cf. A066451.

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

A066479 a(n) = min( x : x^3+n^3+x^2+n^2+x+n=1 mod(x+n)).

Original entry on oeis.org

5, 14, 27, 2, 65, 90, 119, 14, 189, 230, 29, 324, 3, 434, 57, 560, 629, 84, 27, 860, 945, 128, 1127, 1224, 167, 4, 1539, 12, 227, 82, 57, 278, 2277, 44, 2555, 82, 2849, 3002, 417, 3320, 3485, 3654, 5, 4004, 4185, 584, 223, 4752, 4949, 692, 5355, 84, 65, 208, 6215

Offset: 2

Benoit Cloitre, Jan 02 2002

nonn

It appears that a(n) = A014106(n-1) for n in A066049. - Michel Marcus, Feb 17 2021

Cf. A014106, A066451.

a(n) = my(x=0); while(Mod(x^3+n^3+x^2+n^2+x+n, x+n) != 1, x++); x; \\ Michel Marcus, Feb 17 2021

a(n) = A014106(n) for n=2, 3, 4, 6, 7, 8, 10, 11, 13, 15, 17, 18, 21, 22, 24, 25, 28, 34, 36, 38, 39.

More terms from Michel Marcus, Feb 17 2021

cp's OEIS Frontend

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

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