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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

Table of n, a(n) for n=2..45.

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-Fran├žois 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.)