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A174413
Triangle T(n,m) with the denominator of 1/(n-m)^2-1/n^2, read by rows, 1<=m<n.
2
4, 36, 9, 144, 16, 16, 400, 225, 100, 25, 900, 144, 12, 9, 36, 1764, 1225, 784, 441, 196, 49, 3136, 576, 1600, 64, 576, 64, 64, 5184, 3969, 324, 2025, 1296, 81, 324, 81, 8100, 1600, 4900, 225, 100, 400, 900, 25, 100, 12100, 9801, 7744, 5929, 4356, 3025, 1936, 1089, 484, 121
OFFSET
2,1
COMMENTS
Obtained by deleting the last entry in each row of A061036 or by reversing rows in A120073.
LINKS
EXAMPLE
Triangle T(n,m) begins:
4,
36, 9,
144, 16, 16,
400, 225, 100, 25,
900, 144, 12, 9, 36,
1764, 1225, 784, 441, 196, 49,
3136, 576, 1600, 64, 576, 64, 64,
MAPLE
A174413 := proc(n, m) 1/(n-m)^2-1/n^2 ; denom(%) ; end proc:
seq(seq(A174413(n, k), k=1..n-1), n=2..11); # R. J. Mathar, Jan 27 2011
MATHEMATICA
T[n_, m_] := Denominator[1/(n - m)^2 - 1/n^2];
Table[T[n, m], {n, 2, 11}, {m, 1, n-1}] // Flatten (* Jean-François Alcover, May 18 2018 *)
CROSSREFS
Cf. A165441, A172370 (numerators).
Sequence in context: A172282 A120083 A110219 * A162990 A366729 A092960
KEYWORD
nonn,frac,tabl,look,easy
AUTHOR
Paul Curtz, Mar 19 2010
STATUS
approved