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 1-10 of 16 results. Next

A294969 Decimal expansion of sqrt(14)/2 = sqrt(7/2) = A010471/2.

Original entry on oeis.org

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

Views

Author

Wolfdieter Lang, Nov 27 2017

Keywords

Comments

The regular continued fraction of sqrt(14)/2 is [1, repeat(1, 6, 1, 2)].
The convergents are given in A295336/A295337.
sqrt(14)/2 appears in a regular hexagon inscribed in a circle of radius 1 unit in the following way. Draw a straight line through two opposed midpoints of a side (halving the hexagon). The length between one of the midpoints, say M, and one of the two vertices nearest to the opposed midpoint is sqrt(13)/2 = A295330 units. A circle through M with this length ratio sqrt(13)/2 intersects the line below the hexagon at a point, say P. Then the length ratio between P and one of the two vertices nearest to M is sqrt(14)/2 (from a right triangle (1/2, sqrt(13)/2, sqrt(14)/2)).

Examples

			1.87082869338697069279187436615827465087800990388936347315187273366001757815...
		

Crossrefs

Programs

  • Mathematica
    First[RealDigits[Sqrt[14]/2, 10, 100]] (* Paolo Xausa, May 23 2025 *)

A248243 Egyptian fraction representation of sqrt(14) (A010471) using a greedy function.

Original entry on oeis.org

3, 2, 5, 25, 604, 568947, 524109421430, 456412587974094208278324, 217923503007735559214372603301923745039374715408, 53829867761684622028477476025136774072620218179339699337234480313626745601639126196448075512614
Offset: 0

Views

Author

Robert G. Wilson v, Oct 04 2014

Keywords

Crossrefs

Egyptian fraction representations of the square roots: A006487, A224231, A248235-A248322.
Egyptian fraction representations of the cube roots: A129702, A132480-A132574.

Programs

  • Mathematica
    Egyptian[nbr_] := Block[{lst = {IntegerPart[nbr]}, cons = N[ FractionalPart[ nbr], 2^20], denom, iter = 8}, While[ iter > 0, denom = Ceiling[ 1/cons]; AppendTo[ lst, denom]; cons -= 1/denom; iter--]; lst]; Egyptian[ Sqrt[ 14]]

A010123 Continued fraction for sqrt(14).

Original entry on oeis.org

3, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6, 1, 2, 1, 6
Offset: 0

Views

Author

Keywords

Examples

			3.741657386773941385583748732... = 3 + 1/(1 + 1/(2 + 1/(1 + 1/(6 + ...)))). - _Harry J. Smith_, Jun 02 2009
		

References

  • Roger Penrose, "The Road to Reality, A complete guide to the Laws of the Universe", Jonathan Cape, London, 2004, page 56. [From Olivier GĂ©rard, May 22 2009]
  • James J. Tattersall, Elementary Number Theory in Nine Chapters, Cambridge University Press, 1999, page 276.

Crossrefs

Cf. A010471 (decimal expansion).

Programs

  • Mathematica
    ContinuedFraction[Sqrt[14],300] (* Vladimir Joseph Stephan Orlovsky, Mar 05 2011 *)
    PadRight[{3},120,{6,1,2,1}] (* Harvey P. Dale, Jan 16 2017 *)
  • PARI
    { allocatemem(932245000); default(realprecision, 15000); x=contfrac(sqrt(14)); for (n=0, 20000, write("b010123.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 02 2009

Formula

a(n) = 1 + floor((n+2)/4) - floor((n+1)/4) + 5*(floor((n+4)/4) - floor((n+3)/4)) for n > 0. - Wesley Ivan Hurt, Apr 10 2017
From Amiram Eldar, Nov 12 2023: (Start)
Multiplicative with a(2) = 2, a(2^e) = 6 for e >= 2, and a(p^e) = 1 for an odd prime p.
Dirichlet g.f.: zeta(s) * (1 + 1/2^s + 1/2^(2*s-2)). (End)
G.f.: (3 + x + 2*x^2 + x^3 + 3*x^4)/(1 - x^4). - Stefano Spezia, Jul 26 2025

A194395 Numbers m such that Sum_{k=1..m} (<1/2 + k*r> - ) < 0, where r=sqrt(14) and < > denotes fractional part.

Original entry on oeis.org

1, 5, 9, 13, 17, 21, 25, 29, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 45, 47, 48, 49, 51, 52, 53, 55, 56, 57, 59, 63, 67, 71, 75, 79, 83, 87, 121, 125, 129, 133, 137, 141, 145, 149, 151, 152, 153, 155, 156, 157, 159, 160, 161, 163, 164, 165, 167, 168, 169
Offset: 1

Views

Author

Clark Kimberling, Aug 23 2011

Keywords

Comments

See A194368.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[14]; c = 1/2;
    x[n_] := Sum[FractionalPart[k*r], {k, 1, n}]
    y[n_] := Sum[FractionalPart[c + k*r], {k, 1, n}]
    t1 = Table[If[y[n] < x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t1, 1]]       (* A194395 *)
    t2 = Table[If[y[n] == x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t2, 1]]       (* A194396 *)
    t3 = Table[If[y[n] > x[n], 1, 0], {n, 1, 300}];
    Flatten[Position[t3, 1]]       (* A194397 *)

A194396 Numbers m such that Sum_{k=1..m} (<1/2 + k*r> - ) = 0, where r=sqrt(14) and < > denotes fractional part.

Original entry on oeis.org

2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 34, 38, 42, 46, 50, 54, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 94, 98, 102, 106, 110, 114, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150
Offset: 1

Views

Author

Clark Kimberling, Aug 23 2011

Keywords

Comments

Every term is even; see A194368.

Crossrefs

Programs

  • Mathematica
    r = Sqrt[14]; c = 1/2;
    x[n_] := Sum[FractionalPart[k*r], {k, 1, n}]
    y[n_] := Sum[FractionalPart[c + k*r], {k, 1, n}]
    t1 = Table[If[y[n] < x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t1, 1]]       (* A194395 *)
    t2 = Table[If[y[n] == x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t2, 1]]       (* A194396 *)
    t3 = Table[If[y[n] > x[n], 1, 0], {n, 1, 300}];
    Flatten[Position[t3, 1]]       (* A194397 *)

A194397 Numbers m such that Sum_{k=1..m} (<1/2 + k*r> - ) > 0, where r=sqrt(14) and < > denotes fractional part.

Original entry on oeis.org

3, 7, 11, 15, 19, 23, 27, 61, 65, 69, 73, 77, 81, 85, 89, 91, 92, 93, 95, 96, 97, 99, 100, 101, 103, 104, 105, 107, 108, 109, 111, 112, 113, 115, 116, 117, 119, 123, 127, 131, 135, 139, 143, 147, 181, 185, 189, 193, 197, 201, 205, 209, 211, 212, 213, 215
Offset: 1

Views

Author

Clark Kimberling, Aug 23 2011

Keywords

Comments

See A194368.

Crossrefs

Cf. A010471 (sqrt(14)), A194368, A194396, A194397.

Programs

  • Maple
    r:= sqrt(14):
    X:= 0: R:= NULL: count:= 0:
    for n from 1 while count < 100 do
      X:= X + frac(1/2+n*r) - frac(n*r);
      if X > 0 then
        count:= count+1;
        R:= R, n
      fi
    od:
    R; # Robert Israel, Nov 25 2020
  • Mathematica
    r = Sqrt[14]; c = 1/2;
    x[n_] := Sum[FractionalPart[k*r], {k, 1, n}]
    y[n_] := Sum[FractionalPart[c + k*r], {k, 1, n}]
    t1 = Table[If[y[n] < x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t1, 1]]       (* A194395 *)
    t2 = Table[If[y[n] == x[n], 1, 0], {n, 1, 200}];
    Flatten[Position[t2, 1]]       (* A194396 *)
    t3 = Table[If[y[n] > x[n], 1, 0], {n, 1, 300}];
    Flatten[Position[t3, 1]]       (* A194397 *)

A041020 Numerators of continued fraction convergents to sqrt(14).

Original entry on oeis.org

3, 4, 11, 15, 101, 116, 333, 449, 3027, 3476, 9979, 13455, 90709, 104164, 299037, 403201, 2718243, 3121444, 8961131, 12082575, 81456581, 93539156, 268534893, 362074049, 2440979187, 2803053236, 8047085659
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

Formula

G.f.: (3+4*x+11*x^2+15*x^3+11*x^4-4*x^5+3*x^6-x^7)/(1-30*x^4+x^8). - Colin Barker, Jan 03 2012
a(n) = 30*a(n-4) - a(n-8). - Wesley Ivan Hurt, Aug 04 2025

A041021 Denominators of continued fraction convergents to sqrt(14).

Original entry on oeis.org

1, 1, 3, 4, 27, 31, 89, 120, 809, 929, 2667, 3596, 24243, 27839, 79921, 107760, 726481, 834241, 2394963, 3229204, 21770187, 24999391, 71768969, 96768360, 652379129, 749147489, 2150674107, 2899821596, 19549603683, 22449425279, 64448454241, 86897879520
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A010471, A041020, A157878 (quadrisection), A068204 (quadrisection).

Programs

  • Mathematica
    Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[14],n]]],{n,1,50}] (* Vladimir Joseph Stephan Orlovsky, Mar 17 2011*)
    Convergents[Sqrt[14],30]//Denominator (* or *) LinearRecurrence[{0,0,0,30,0,0,0,-1},{1,1,3,4,27,31,89,120},30] (* Harvey P. Dale, Aug 17 2024 *)

Formula

G.f.: (1+1*x+3*x^2+4*x^3-3*x^4+x^5-x^6)/(1-30*x^4+x^8). - Colin Barker, Jan 03 2012

A176217 Decimal expansion of (14+4*sqrt(14))/7.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 12 2010

Keywords

Comments

Continued fraction expansion of (14+4*sqrt(14))/7 is A010712.

Examples

			(14+4*sqrt(14))/7 = 4.13808993529939507747...
		

Crossrefs

Cf. A010471 (decimal expansion of sqrt(14)), A010712 (repeat 4, 7).

Programs

  • Mathematica
    RealDigits[(14+4Sqrt[14])/7,10,120][[1]] (* Harvey P. Dale, Jan 24 2015 *)

A177033 Decimal expansion of (2+sqrt(14))/4.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, May 01 2010

Keywords

Comments

Continued fraction expansion of (2+sqrt(14))/4 is A068073.

Examples

			(2+sqrt(14))/4 = 1.43541434669348534639...
		

Crossrefs

Cf. A010471 (decimal expansion of sqrt(14)), A068073 (repeat 1, 2, 3, 2).

Programs

  • Mathematica
    RealDigits[(2+Sqrt[14])/4,10,120][[1]] (* Harvey P. Dale, Jul 18 2011 *)
Showing 1-10 of 16 results. Next