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.

Showing 1-2 of 2 results.

A176400 Decimal expansion of sqrt(483).

Original entry on oeis.org

2, 1, 9, 7, 7, 2, 6, 0, 9, 7, 5, 8, 3, 5, 9, 1, 0, 5, 6, 7, 2, 0, 1, 6, 3, 5, 8, 6, 0, 8, 9, 5, 5, 5, 0, 9, 1, 6, 5, 1, 5, 9, 2, 5, 7, 7, 0, 1, 9, 9, 3, 1, 6, 5, 6, 1, 7, 9, 8, 0, 8, 7, 9, 8, 8, 1, 4, 1, 9, 4, 8, 6, 5, 0, 6, 2, 0, 8, 2, 1, 0, 8, 0, 7, 0, 6, 1, 1, 6, 7, 7, 4, 1, 6, 7, 7, 2, 4, 2, 5, 8, 3, 0, 5, 6
Offset: 2

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Author

Klaus Brockhaus, Apr 17 2010

Keywords

Comments

Continued fraction expansion of sqrt(483) is A040461.

Examples

			sqrt(483) = 21.97726097583591056720...
		

Crossrefs

Cf. A010477 (decimal expansion of sqrt(21)), A010479 (decimal expansion of sqrt(23)), A176399 (decimal expansion of (21+sqrt(483))/7), A040461.

Programs

  • Mathematica
    RealDigits[Sqrt[483],10,120][[1]] (* Harvey P. Dale, Oct 09 2015 *)

A041923 Denominators of continued fraction convergents to sqrt(483).

Original entry on oeis.org

1, 1, 43, 44, 1891, 1935, 83161, 85096, 3657193, 3742289, 160833331, 164575620, 7073009371, 7237584991, 311051578993, 318289163984, 13679196466321, 13997485630305, 601573592939131, 615571078569436, 26455558892855443, 27071129971424879
Offset: 0

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Author

Keywords

Comments

The following remarks assume an offset of 1. This is the sequence of Lehmer numbers U_n(sqrt(R),Q) for the parameters R = 42 and Q = -1; it is a strong divisibility sequence, that is, gcd(a(n),a(m)) = a(gcd(n,m)) for all positive integers n and m. Consequently, this is a divisibility sequence: if n divides m then a(n) divides a(m). - Peter Bala, May 27 2014

Crossrefs

Programs

  • Magma
    I:=[1,1,43,44]; [n le 4 select I[n] else 44*Self(n-2)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 27 2013
  • Mathematica
    Denominator[Convergents[Sqrt[483], 30]] (* Vincenzo Librandi, Dec 27 2013 *)

Formula

G.f.: -(x^2 -x -1) / (x^4 -44*x^2 +1). - Colin Barker, Nov 27 2013
a(n) = 44*a(n-2) - a(n-4) for n > 3. - Vincenzo Librandi, Dec 27 2013
From Peter Bala, May 27 2014: (Start)
The following remarks assume an offset of 1.
Let alpha = ( sqrt(42) + sqrt(46) )/2 and beta = ( sqrt(42) - sqrt(46) )/2 be the roots of the equation x^2 - sqrt(42)*x - 1 = 0. Then a(n) = (alpha^n - beta^n)/(alpha - beta) for n odd, while a(n) = (alpha^n - beta^n)/(alpha^2 - beta^2) for n even.
a(n) = Product_{k = 1..floor((n-1)/2)} ( 42 + 4*cos^2(k*Pi/n) ).
Recurrence equations: a(0) = 0, a(1) = 1 and for n >= 1, a(2*n) = a(2*n - 1) + a(2*n - 2) and a(2*n + 1) = 42*a(2*n) + a(2*n - 1). (End)

Extensions

More terms from Colin Barker, Nov 27 2013
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