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A124525
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 either divide m or are coprime to n.
2
1, 1, 1, 2, 3, 2, 3, 4, 4, 2, 4, 7, 8, 6, 4, 5, 6, 9, 4, 9, 2, 6, 9, 10, 13, 14, 6, 6, 7, 8, 15, 8, 19, 4, 13, 2, 8, 13, 13, 16, 23, 15, 19, 10, 7, 9, 10, 16, 12, 26, 7, 25, 7, 12, 3, 10, 13, 23, 24, 31, 18, 31, 25, 21, 12, 10, 11, 12, 21, 15, 36, 11, 38, 19, 25, 11, 21, 3, 12, 19, 22, 24, 39
OFFSET
1,4
LINKS
EXAMPLE
The first 4 columns and first 6 rows (excluding t(6,4)) of the table are:
1, 1, 2, 2
1, 3, 4, 6
2, 4, 8, 4
3, 7, 9, 13
4, 6, 10, 8
5, 9, 15
The number of these terms which either divide 6 or are coprime to 4 is 16 (the odd integers, the 2's and the 6's). So t(6,4) = 16.
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, 13}, {i, d}]] (* Ray Chandler, Nov 11 2006 *)
CROSSREFS
Cf. A124524.
Sequence in context: A072106 A124524 A303543 * A106788 A123175 A143998
KEYWORD
nonn,tabl
AUTHOR
Leroy Quet, Nov 04 2006
EXTENSIONS
Extended by Ray Chandler, Nov 11 2006
STATUS
approved