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.

A010537 Decimal expansion of square root of 86.

Original entry on oeis.org

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

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Comments

Continued fraction expansion is 9 followed by {3, 1, 1, 1, 8, 1, 1, 1, 3, 18} repeated. - Harry J. Smith, Jun 10 2009

Examples

			9.273618495495703752516416073990174626263468912076298213373826598328236...
		

Crossrefs

Cf. A010159 (continued fraction).

Programs

  • Mathematica
    RealDigits[N[Sqrt[86],200]][[1]] (* Vladimir Joseph Stephan Orlovsky, Feb 04 2012 *)
  • PARI
    { default(realprecision, 20080); x=sqrt(86); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b010537.txt", n, " ", d)); } \\ Harry J. Smith, Jun 10 2009

A041153 Denominators of continued fraction convergents to sqrt(86).

Original entry on oeis.org

1, 3, 4, 7, 11, 95, 106, 201, 307, 1122, 20503, 62631, 83134, 145765, 228899, 1976957, 2205856, 4182813, 6388669, 23348820, 426667429, 1303351107, 1730018536, 3033369643, 4763388179, 41140475075, 45903863254, 87044338329, 132948201583, 485888943078
Offset: 0

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Crossrefs

Programs

  • Magma
    I:=[1, 3, 4, 7, 11, 95, 106, 201, 307, 1122, 20503, 62631, 83134, 145765, 228899, 1976957, 2205856, 4182813, 6388669, 23348820]; [n le 20 select I[n] else 20810*Self(n-10)-Self(n-20): n in [1..40]]; // Vincenzo Librandi, Dec 12 2013
  • Mathematica
    Denominator/@Convergents[Sqrt[86], 50] (* Vladimir Joseph Stephan Orlovsky, Jul 05 2011 *)
    CoefficientList[Series[-(x^18 - 3 x^17 + 4 x^16 - 7 x^15 + 11 x^14 - 95 x^13 + 106 x^12 - 201 x^11 + 307 x^10 - 1122 x^9 - 307 x^8 - 201 x^7 - 106 x^6 - 95 x^5 - 11 x^4 - 7 x^3 - 4 x^2 - 3 x - 1)/(x^20 - 20810 x^10 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 12 2013 *)

Formula

G.f.: -(x^18 -3*x^17 +4*x^16 -7*x^15 +11*x^14 -95*x^13 +106*x^12 -201*x^11 +307*x^10 -1122*x^9 -307*x^8 -201*x^7 -106*x^6 -95*x^5 -11*x^4 -7*x^3 -4*x^2 -3*x-1) / (x^20-20810*x^10+1). - Colin Barker, Nov 13 2013
a(n) = 20810*a(n-10) - a(n-20). - Vincenzo Librandi, Dec 12 2013
Showing 1-2 of 2 results.