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 A120073 Denominator triangle for hydrogen spectrum rationals. 10
 4, 9, 36, 16, 16, 144, 25, 100, 225, 400, 36, 9, 12, 144, 900, 49, 196, 441, 784, 1225, 1764, 64, 64, 576, 64, 1600, 576, 3136, 81, 324, 81, 1296, 2025, 324, 3969, 5184, 100, 25, 900, 400, 100, 225, 4900, 1600 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS The corresponding numerator triangle is A120072. See A120072 and A120070 for more details. LINKS W. Lang: First ten rows, rationals and more. FORMULA a(m,n)=denominator(r(m,n)) with r(m,n):=1/n^2 - 1/m^2, m>=2, n=1..m-1. MATHEMATICA Table[ Table[1/n^2 - 1/m^2 // Denominator, {n, 1, m-1}], {m, 2, 10}] // Flatten (* Jean-François Alcover, Sep 16 2013 *) CROSSREFS Row sums give A120075. Cf. A126252. Sequence in context: A182723 A176607 A134815 * A056894 A272145 A272221 Adjacent sequences:  A120070 A120071 A120072 * A120074 A120075 A120076 KEYWORD nonn,easy,tabl,frac AUTHOR Wolfdieter Lang, Jul 20 2006 STATUS approved

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Last modified January 25 11:03 EST 2022. Contains 350567 sequences. (Running on oeis4.)