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 A195565 Denominators a(n) of Pythagorean approximations b(n)/a(n) to 5/4. 4
 4, 3, 204, 280, 2280, 12596, 12797, 831996, 1149440, 9341440, 51622404, 52441603, 3409523404, 4710402840, 38281220840, 211548594996, 214905676797, 13972226073596, 19303229690880, 156876433658880, 866926090675204, 880683411072003 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A195500 for a discussion and references. LINKS Table of n, a(n) for n=1..22. MATHEMATICA r = 5/4; z = 26; p[{f_, n_}] := (#1[[2]]/#1[[ 1]] &)[({2 #1[[1]] #1[[2]], #1[[1]]^2 - #1[[ 2]]^2} &)[({Numerator[#1], Denominator[#1]} &)[ Array[FromContinuedFraction[ ContinuedFraction[(#1 + Sqrt[1 + #1^2] &)[f], #1]] &, {n}]]]]; {a, b} = ({Denominator[#1], Numerator[#1]} &)[ p[{r, z}]] (* A195565, A195566 *) Sqrt[a^2 + b^2] (* A195567 *) (* by Peter J. C. Moses, Sep 02 2011 *) CROSSREFS Cf. A195500, A195566, A195567. Sequence in context: A325871 A079324 A002298 * A368301 A356855 A335913 Adjacent sequences: A195562 A195563 A195564 * A195566 A195567 A195568 KEYWORD nonn AUTHOR Clark Kimberling, Sep 21 2011 STATUS approved

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Last modified June 22 03:16 EDT 2024. Contains 373561 sequences. (Running on oeis4.)