A124524 Table (read by antidiagonals) where t(1,1) = 1, t(m,n) = number of terms above and to the left of t(m,n) (i.e., number of t(k,j)'s, where 1 <= k <= m, 1 <= j <= n, excluding the t(m,n) case itself) which both divide m and are coprime to n.

1, 1, 1, 2, 3, 2, 3, 4, 4, 2, 2, 3, 3, 3, 2, 5, 3, 7, 6, 6, 2, 2, 7, 3, 3, 6, 3, 2, 5, 4, 6, 3, 9, 3, 8, 2, 3, 3, 5, 12, 3, 3, 8, 3, 2, 7, 9, 10, 5, 22, 3, 11, 9, 10, 2, 2, 5, 3, 3, 5, 3, 3, 3, 3, 3, 2, 8, 3, 12, 17, 12, 5, 30, 3, 13, 11, 12, 2, 2, 10, 3, 8, 19, 3, 3, 22, 3, 3, 11, 3, 2, 8, 3, 11, 3, 9, 3

Offset

1,4

Links

Table of n, a(n) for n=1..97.

Example

The first 4 columns and first 6 rows (excluding t(6,4)) of the table are:
  1, 1, 2, 2
  1, 3, 4, 3
  2, 4, 3, 6
  3, 3, 7, 3
  2, 3, 3, 3
  5, 7, 6,
The number of these terms which both divide 6 and are coprime to 4 is 12 (the 1's and the 3's). So t(6,4) = 12.

Mathematica

t[1, 1] = 1; t[m_, n_] := t[m, n] = Block[{c = 0}, Do[ Do[ If[k == m && j == n, Continue[]]; If[Mod[m, t[k, j]] == 0 && GCD[t[k, j], n] == 1, c++ ]; , {j, n}]; , {k, m}]; c]; Flatten[Table[t[d + 1 - i, i], {d, 14}, {i, d}]] (* Ray Chandler, Nov 11 2006 *)

Crossrefs

Cf. A124525.

Sequence in context: A326820 A095161 A072106 * A303543 A124525 A106788

Adjacent sequences: A124521 A124522 A124523 * A124525 A124526 A124527

Keyword

nonn,tabl

Author

Leroy Quet, Nov 04 2006

Extensions

Extended by Ray Chandler, Nov 11 2006

Status

approved