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 A215656 Solution R of (2*u)^2 = R^2 - p*S^2, where p is the n-th prime of the form 4k+1. 1
 147, 20522387091091, 89544370675021535714607142, 8801866915656397716021519532258687362772409962179980790374047406788427 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS p = A002144(n), u = A215615(p), and S = A215657(n). A215615 is computed from Wendt's circulant determinant A048954. Brown and Chamberland (2012, p. 600) give explicit formulas for u, R, S. LINKS Ezra Brown and Marc Chamberland, Generalizing Gauss's gem, Amer. Math. Monthly, 119 (Aug. 2012), 597-601. FORMULA a(n) = sqrt(4*u^2 + p*S^2) with S = A215657(n), p = A002144(n), u = A215615(p). EXAMPLE 2*A215615(5) = 2*11 = 22 and 22^2  = 147^2 - 5*65^2, so a(1) = 147. CROSSREFS Cf. A002144, A048954, A215615, A215657. Sequence in context: A075925 A097729 A214139 * A308889 A214619 A061154 Adjacent sequences:  A215653 A215654 A215655 * A215657 A215658 A215659 KEYWORD nonn AUTHOR Jonathan Sondow, Aug 19 2012 STATUS approved

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Last modified August 15 13:27 EDT 2020. Contains 336504 sequences. (Running on oeis4.)