A093594 Farey-factorial numerators, including duplicates.

1, 1, 2, 2, 3, 4, 6, 6, 8, 12, 16, 18, 24, 24, 30, 40, 48, 60, 72, 80, 90, 96, 120, 120, 144, 180, 240, 288, 360, 432, 480, 540, 576, 600, 720, 720, 840, 1008, 1260, 1440, 1680, 2016, 2160, 2520, 2880, 3024, 3360, 3600, 3780, 4032, 4200, 4320, 5040, 5040, 5760

Offset

1,3

Comments

The only repeated terms are 1!, 2!, 3!, etc. Deleting one of each leaves A092824. When written as an array with (row n)=n!*(Farey fractions of order n), The row sums are given by A093593. The n-th alternating row sum is n!/2, for n>=2. (2/n!)*(n-th row sum)=A005728(n)=number of Farey fractions of order n.

Links

Table of n, a(n) for n=1..55.

Example

Put the positive Farey fractions of order n into row n,
and multiply by n!:
1
1 2
2 3 4 6
6 8 12 16 18 24 ...
Link the rows to form the sequence.

Crossrefs

Cf. A005728, A092824, A093593.

Sequence in context: A101344 A152048 A046934 * A008806 A356607 A366843

Adjacent sequences: A093591 A093592 A093593 * A093595 A093596 A093597

Keyword

nonn,tabf

Author

Clark Kimberling, Apr 03 2004

Status

approved