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 1-9 of 9 results.

A233588 Decimal expansion of the continued fraction prime(1) + prime(1)/(prime(2) + prime(2)/(prime(3) + prime(3)/(prime(4) + prime(4)/...))).

Original entry on oeis.org

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

Views

Author

Stanislav Sykora, Jan 02 2014

Keywords

Comments

Given a nondecreasing sequence s(n) of natural numbers (such as, in this case, that of primes A000079), the corresponding continued fraction is bf(s(n)) = a(1) + a(1)/(a(2) + a(2)/(a(3) + a(3)/(...))).
For the inverse of this mapping of nondecreasing sequences of natural numbers into irrational real numbers greater than 1, see A233582.

Examples

			2.56654383217138884446752910633228575178297282870231464596973352546639971...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[ Fold[(#2 + #2/#1) &, 1, Reverse@ Prime@ Range@ 57], 10, 111][[1]] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    See the link.

Formula

Equals 2 + 2/(3 + 3/(5 + 5/(7 + 7/(11 + 11/(13 + 13/(17 + ...)))))).

A233583 Coefficients of the generalized continued fraction expansion e = a(1) +a(1)/(a(2) +a(2)/(a(3) +a(3)/(a(4) +a(4)/....))).

Original entry on oeis.org

2, 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56
Offset: 1

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details on Blazys' expansion, see A233582.
This sequence matches that of natural numbers (A000027), offset by 1, with two different starting terms.

Crossrefs

Cf. A000027 (natural numbers), A001113 (number e).
Cf. Blazys' expansions: A233582 (Pi), A233584, A233585, A233586, A233587 and Blazys' continued fractions: A233588, A233589, A233590, A233591.

Programs

  • Mathematica
    BlazysExpansion[n_, mx_] := Block[{k = 1, x = n, lmt = mx + 1, s, lst = {}}, While[k < lmt, s = Floor[x]; x = 1/(x/s - 1); AppendTo[lst, s]; k++]; lst]; BlazysExpansion[E, 80] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    default(realprecision,100);
    bx(x,nmax)={local(c,v,k); \\ Blazys expansion function
    v = vector(nmax);c = x;for(k=1,nmax,v[k] = floor(c);c = v[k]/(c-v[k]););return (v);}
    bx(exp(1),100) \\ Execution; use high real precision

Formula

e = 2+2/(2+2/(2+2/(3+3/(4+4/(5+...))))).

A233584 Coefficients of the generalized continued fraction expansion sqrt(e) = a(1) +a(1)/(a(2) +a(2)/(a(3) +a(3)/(a(4) +a(4)/....))).

Original entry on oeis.org

1, 1, 1, 1, 5, 9, 17, 109, 260, 2909, 3072, 3310, 3678, 6715, 35175, 37269, 439792, 1400459, 1472451, 4643918, 5683171, 44850176, 62252861, 145631385, 154435765, 371056666, 1685980637, 11196453405, 14795372939
Offset: 1

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details on Blazys' expansions, see A233582.
Compared with simple continued fraction expansion for sqrt(e), this sequence starts soon growing very rapidly.

Crossrefs

Cf. A019774 (sqrt(e)), A058281 (simple continued fraction).
Cf. Blazys' expansions: A233582 (Pi), A233583, A233585, A233586, A233587 and Blazys' continued fractions: A233588, A233589, A233590, A233591.

Programs

  • Mathematica
    BlazysExpansion[n_, mx_] := Block[{k = 1, x = n, lmt = mx + 1, s, lst = {}}, While[k < lmt, s = Floor[x]; x = 1/(x/s - 1); AppendTo[lst, s]; k++]; lst]; BlazysExpansion[Sqrt@E, 35] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    bx(x, nmax)={local(c, v, k); \\ Blazys expansion function
    v = vector(nmax); c = x; for(k=1, nmax, v[k] = floor(c); c = v[k]/(c-v[k]); ); return (v); }
    bx(exp(1/2), 100) \\ Execution; use high real precision

Formula

sqrt(e) = 1+1/(1+1/(1+1/(1+1/(5+5/(9+9/(17+17/(109+...))))))).

A233585 Coefficients of the generalized continued fraction expansion of the inverse of Euler constant, 1/gamma = a(1) +a(1)/(a(2) +a(2)/(a(3) +a(3)/(a(4) +a(4)/....))).

Original entry on oeis.org

1, 1, 2, 2, 2, 2, 4, 12, 39, 71, 83, 484, 1028, 1447, 9913, 31542, 526880, 685669, 1396494, 1534902, 2295194, 9521643, 9643315, 42421746, 183962859, 553915624, 557976754, 6111180351, 10671513549, 61650520975, 106532505646
Offset: 1

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Crossrefs

Cf. A233582.
Cf. A001620 (gamma).
Cf. Blazys's expansions: A233582 (Pi), A233583(e), A233584 (sqrt(e)), A233586 (2*gamma), A233587 and Blazys's continued fractions: A233588, A233589, A233590, A233591.

Programs

  • Mathematica
    BlazysExpansion[n_, mx_] := Block[{k = 1, x = n, lmt = mx + 1, s, lst = {}}, While[k < lmt, s = Floor[x]; x = 1/(x/s - 1); AppendTo[lst, s]; k++]; lst]; BlazysExpansion[1/EulerGamma, 35] (* Robert G. Wilson v, May 22 2014 *)
    BlazysExpansion[n_, mx_] := Reap[Nest[(1/(#/Sow[Floor[#]] - 1)) &, n, mx];][[-1, 1]]; BlazysExpansion[1/EulerGamma, 35] (* Jan Mangaldan, Jan 04 2017 *)
  • PARI
    bx(x, nmax)={local(c, v, k); \\ Blazys expansion function
    v = vector(nmax); c = x; for(k=1, nmax, v[k] = floor(c); c = v[k]/(c-v[k]); ); return (v); }
    bx(1/Euler, 670) \\ Execution; use very high real precision

Formula

1/gamma = 1+1/(1+1/(2+2/(2+2/(2+2/(2+2/(4+4/(12+...))))))).

A233589 Decimal expansion of the continued fraction c(1) +c(1)/(c(2) +c(2)/(c(3) +c(3)/(c(4) +c(4)/....))), where c(i)=(i-1)!.

Original entry on oeis.org

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

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Examples

			1.69880476767000721195269011591464043255973093664983969781741917426892...
		

Crossrefs

Cf. A233588.
Cf. A000142 (factorials), A006882 (double factorials).
Cf. Blazys' continued fractions: A233588, A233590, A233591 and Blazys' expansions: A233582, A233583, A233584, A233585, A233586, A233587.

Programs

  • Mathematica
    RealDigits[ Fold[(#2 + #2/#1) &, 1, Reverse@ Range[0, 18]!], 10, 111][[1]] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    See the link.

Formula

Equals 0!+0!/(1!+1!/(2!+2!/(3!+3!/(4!+...)))).
Equals simple continued fraction [0!!; 1!!, 2!!, 3!!, ..., n!!, ...] where the double factorial n!! = A006882(n). - Thomas Ordowski, Oct 21 2024

A233590 Decimal expansion of the continued fraction c(1) +c(1)/(c(2) +c(2)/(c(3) +c(3)/(c(4) +c(4)/....))), where c(i)=2^(i-1).

Original entry on oeis.org

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

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details about this type of continued fraction, see A233588.
This one corresponds to the powers of two sequence.
Corresponds to the regular continued fraction 1,2,2,4,4,8,8,16,16,... = A060546. - Jeffrey Shallit, Jun 14 2016

Examples

			1.408615979735005205132362590255795209484563373686888353703927022...
		

Crossrefs

Cf. A000079 (2^n), A096658, A060546.
Cf. Blazys's continued fractions: A233588, A233589, A233591 and Blazys' expansions: A233582, A233583, A233584, A233585, A233586, A233587

Programs

  • Mathematica
    RealDigits[ Fold[(#2 + #2/#1) &, 1, Reverse@ (2^Range[0, 27])], 10, 111][[1]] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    See the link

Formula

Equals 1+1/(2+2/(4+4/(8+8/(16+16/(32+...))))).
Equals Product_{k>=0} ((1 - 2^(5*k + 2))*(1 - 2^(5*k + 3)))/((1 - 2^(5*k + 1))*(1 - 2^(5*k + 4))). - Antonio GraciĆ” Llorente, Mar 20 2024

A233591 Decimal expansion of the continued fraction c(1) +c(1)/(c(2) +c(2)/(c(3) +c(3)/(c(4) +c(4)/....))), where c(i)=i^2.

Original entry on oeis.org

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

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details on this type of continued fractions, see A233588.
This one corresponds to the squares of natural numbers.

Examples

			1.22628402418269027481493710086224039619081148735362359550166652...
		

Crossrefs

Cf. A000290 (n^2).
Cf. Blazys' continued fractions: A233588, A233589, A233591 and Blazys' expansions: A233582, A233583, A233584, A233585, A233586, A233587.

Programs

  • Mathematica
     RealDigits[ Fold[(#2 + #2/#1) &, 1, Reverse@ Range[45]^2], 10, 111][[1]] (* Robert G. Wilson v, May 22 2014 *)
  • PARI
    See the link

Formula

Equals 1+1/(4+4/(9+9/(16+16/(25+25/(36+...))))).

A233592 Positive integers k such that the continued fraction expansion sqrt(k) = c(1) + c(1)/(c(2) + c(2)/(c(3) + c(3)/...)) is periodic.

Original entry on oeis.org

2, 3, 5, 6, 8, 10, 11, 12, 15, 17, 18, 20, 24, 26, 27, 30, 35, 37, 38, 39, 40, 42, 44, 45, 48, 50, 51, 56, 63, 65, 66, 68, 72, 80, 82, 83, 84, 87, 90, 99, 101, 102, 104, 105, 108, 110, 120, 122, 123, 132, 143, 145
Offset: 1

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details on this type of expansion, see A233582.
The cases with aperiodic expansions are listed in A233593.
All the listed cases become periodic after just two leading terms (it is a conjecture that this behavior is general); the validity of their expansions was explicitly tested.

Examples

			Blazys's expansion of sqrt(2) is {1, 2, 4, 4, 4, 4, 4, ...}, i.e., it has a periodic termination. Consequently, 2 is a term of this sequence.
		

Crossrefs

Cf. A233593.
Cf. Blazys's expansions: A233582, A233584, A233585, A233586, A233587.

Programs

  • PARI
    See the link.

A233593 Positive integers k such that the continued fraction expansion sqrt(k) = c(1) + c(1)/(c(2) + c(2)/(c(3) + c(3)/....)) is aperiodic.

Original entry on oeis.org

7, 13, 14, 19, 21, 22, 23, 28, 29, 31, 32, 33, 34, 41, 43, 46, 47, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 67, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 85, 86, 88, 89, 91, 92, 93, 94, 95, 96, 97, 98, 103, 106, 107
Offset: 1

Views

Author

Stanislav Sykora, Jan 06 2014

Keywords

Comments

For more details about this type of expansions, see A233582.
The cases with known periodic expansions, listed in A233592, all become periodic after just two leading terms. In contrast, the Blazys's expansion of sqrt(a(k)) for every member a(k) of this list remains aperiodic up to at least 1000 terms. It is therefore conjectured, though not proved, that these expansions are indeed aperiodic.

Examples

			Blazys's expansion of sqrt(7), A233587, is {2, 3, 30, 34, 111, ...}. Its first 1000 terms are all distinct. Hence, 7 is a term of this sequence.
		

Crossrefs

Cf. A233592.
Cf. Blazys's expansions: A233582, A233584, A233585, A233586, A233587.
Showing 1-9 of 9 results.