A112790 Array where a(1,1)=1 and m-th term of n-th row is number of terms of (n-1)th row which are coprime to the m-th divisor of n.

1, 1, 1, 2, 2, 2, 0, 0, 3, 1, 2, 2, 1, 1, 4, 4, 2, 0, 0, 0, 4, 1, 1, 3, 2, 3, 2, 4, 4, 2, 0, 2, 0, 0, 0, 6, 2, 2, 0, 2, 0, 4, 2, 2, 2, 4, 0, 0, 0, 0, 5, 1, 2, 2, 2, 2, 2, 2, 6, 6, 2, 0, 0, 2, 0, 0, 6, 2, 2, 2, 4, 0, 4, 0, 4, 2, 2, 0, 2, 0, 0, 0, 0, 0, 8, 2, 2, 3, 0, 3, 0, 4, 0, 0, 0, 4, 0, 0, 1, 0, 0, 6, 2, 2, 0

Offset

1,4

Comments

Number of terms in row n is A000005(n).

Links

Table of n, a(n) for n=1..105.

Example

The irregular array's 5th row is [3,1]. The divisors of 6 are 1, 2, 3 and 6. In the 5th row there are 2 terms coprime to 1, 2 terms coprime to 2, 1 term coprime to 3 and 1 term coprime to 6. So the 6th row of the array is [2,2,1,1].
Array starts
1;
1,1;
2,2;
2,0,0;
3,1;
2,2,1,1;
4,4;
2,0,0,0;

Crossrefs

Cf. A000005, A112791.

Sequence in context: A262048 A034852 A212438 * A329922 A179835 A110857

Adjacent sequences: A112787 A112788 A112789 * A112791 A112792 A112793

Keyword

nonn,tabf

Author

Leroy Quet, Dec 31 2005

Extensions

More terms from R. J. Mathar, Aug 29 2007

Status

approved