cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A351862 Denominators of the coefficients in a series for the angles in the Spiral of Theodorus.

Original entry on oeis.org

1, 6, 120, 840, 8064, 4224, 2196480, 199680, 5013504, 74088448, 1568931840, 1899233280, 2411724800, 2831155200, 8757706752, 6968215339008, 76890652016640, 1488206168064, 289223097712640, 74371653697536, 2197648866017280, 10176804748787712, 29785769996451840
Offset: 0

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Author

Robert B Fowler, Feb 22 2022

Keywords

Comments

S(i) is the sum of the angles in the first i-1 triangles of the Spiral of Theodorus (in radians). [corrected by Robert B Fowler, Oct 23 2022]
S(i) = K + sqrt(i) * (2 + 1/(6*i) - 1/(120*i^2) - 1/(840*i^3) + ...) where K is Hlawka's Schneckenkonstante = A105459 * (-1) = -2.1577829966... .
The coefficients in the polynomial series are A351861(n)/a(n). The series is asymptotic, but is accurate for even very low values of i.
See A351861 for the numerators, as well as references, links, and crossrefs.

Examples

			2/1 + 1/(6*i) - 1/(120*i^2) - 1/(840*i^3) + ...
		

Crossrefs

Cf. A351861 (numerators).

Programs

  • Mathematica
    c[0] = 2; c[n_] := ((2*n - 2)!/(n - 1)!) * Sum[(-1)^(n + 1) * BernoulliB[n - k] * k!/(4^(n - k - 1) * (2*k + 1)! * (n - k)!), {k, 0, n}]; Denominator @ Array[c, 30, 0] (* Amiram Eldar, Feb 22 2022 *)
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