A112792 - OEIS

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A112792

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 positive integer coprime to n and <=n.

1, 1, 1, 1, 2, 2, 2, 0, 2, 0, 4, 2, 2, 0, 2, 0, 2, 0, 6, 3, 3, 3, 4, 3, 3, 4, 4, 3, 6, 3, 6, 3, 4, 2, 0, 2, 4, 0, 4, 2, 0, 2, 10, 7, 7, 7, 4, 3, 4, 3, 3, 3, 1, 3, 4, 3, 4, 3, 12, 5, 12, 5, 12, 12, 6, 2, 2, 6, 2, 6, 6, 2, 8, 4, 8, 8, 4, 8, 8, 4, 8, 0, 8, 0, 8, 0, 8, 0, 8, 0, 8, 0, 8, 0, 8, 0, 16, 8

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,5

COMMENTS

Number of terms in row n is A000010(n).

For the purpose of this sequence, GCD(0,n)=n. Since being "coprime" means that the greatest divisor common to two numbers is 1, 0 is only coprime to 1. [From Diana L. Mecum, Aug 07 2008]

LINKS

Diana Mecum, Table of n, a(n) for n = 1..9832 [From Diana L. Mecum, Aug 07 2008]

EXAMPLE

The irregular array's 5th row is [2,0,2,0]. The integers coprime to 6 and <= 6 are 1 and 5. In the 5th row there are 4 terms coprime to 1 and there are 2 terms coprime to 5. So the 6th row of the array is [4,2].

CROSSREFS

Cf. A000010, A112793.

Sequence in context: A176154 A274718 A028930 * A138319 A217864 A002100

Adjacent sequences: A112789 A112790 A112791 * A112793 A112794 A112795

KEYWORD

nonn,tabf,look

AUTHOR

Leroy Quet, Dec 31 2005

EXTENSIONS

Terms 33 through 9832 (with b-file) from Diana L. Mecum, Aug 07 2008

STATUS

approved