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 1-5 of 5 results.

A199657 Numerators of lower rational approximants of Pi with the first 5 terms given by Adam Adamandy Kochański in 1685, continued using a reconstruction by Fukś that is highly likely to match Kochański's incompletely published method.

Original entry on oeis.org

25, 333, 1667438, 9252915567, 136727214560643, 4607472064276325091, 281395884679127288508771, 31300458157678523147391901818, 3630416277654441522583270655032758, 631040767628866632706111841438119582182, 355477406146830706663807382201012685829049871, 215421112450033407479085892668138597831784081541979
Offset: 1

Views

Author

Jonathan Vos Post, Nov 08 2011

Keywords

Comments

The corresponding denominators are given in A199658.
The reconstruction refers to the calculation of the "genitores" in A191642, for which Kochański only announced that he would describe them in more detail in a future work: "I will explain the aforementioned method more completely in Polymathic thoughts and inventions, which work, if God prolongs my life, I have decided to put out for public benefit" (translation from Latin by H. Fukś).

Examples

			a(1) = 25 because Kochański's first lower bound was 25/8 = a(1)/A199658(1) and his first upper bound was 22/7 = A199671(1)/A199672(1).
a(2) = R(1) * A191642(1) + 3 = 22*15 + 3 = 330 + 3 = 333,
R(2) = R(1) * (A191642(1) + 1 ) + 3 = 22*(15 + 1) + 3 = 355 = A199671(2).
		

Crossrefs

Formula

a(1) = 25; R(1) = A199671(1) = 22;
a(n) = R(n-1)*A191642(n-1) + 3, where A191642 are Kochański's "genitores";
R(n) = R(n-1)*(A191642(n-1) + 1) + 3;

Extensions

More terms from Hugo Pfoertner, Mar 07 2020

A199658 Denominators of lower rational approximants of Pi with the first 5 terms given by Adam Adamandy Kochański in 1685, continued using a reconstruction by Fukś that is highly likely to match Kochański's incompletely published method.

Original entry on oeis.org

8, 106, 530762, 2945294501, 43521624105025, 1466603908374792097, 89571092024800092397857, 9963245273671152951934207006, 1155597392139966274078899403965586, 200866514921276434616104042029044754594, 113151972691506812691685713772827327500605957, 68570669785555705551463950663318228291679702401993
Offset: 1

Views

Author

Jonathan Vos Post, Nov 08 2011

Keywords

Comments

The corresponding numerators are given in A199657.
See A199657 for more information and references.

Examples

			a(1) = 8 because Kochański's first lower bound was 25/8 = A199657(1)/a(1) and his first upper bound was 22/7 = A199671(1)/A199672(1).
a(2) = S(1) * A191642(1) + 1 = 7*15 + 1 = 105 + 1 = 106,
S(2) = S(1) * (A191642(1) + 1 ) + 1 = 7*(15 + 1) + 1 = 113 = A199672(2).
		

Crossrefs

Formula

a(1) = 8; S(1) = A199672(1) = 7;
a(n) = S(n-1)*A191642(n-1) + 1, where A191642 are Kochański's "genitores";
S(n) = S(n-1)*(A191642(n-1) + 1) + 1;

Extensions

More terms from Hugo Pfoertner, Mar 07 2020

A199671 Numerators of upper rational approximants of Pi with the first 5 terms given by Adam Adamandy Kochański in 1685, continued using a reconstruction by Fukś that is highly likely to match Kochański's incompletely published method.

Original entry on oeis.org

22, 355, 1667793, 9254583360, 136736469144003, 4607608800745469094, 281400492287928033977865, 31300739558170811075425879683, 3630447578393999693394346080912441, 631044398076445026705805235784200494623, 355478037191228783108834088006248470029544494, 215421467928070598707869001502226604080254111086473
Offset: 1

Views

Author

Jonathan Vos Post, Nov 08 2011

Keywords

Comments

The corresponding denominators are given in A199672.
See A199657 for more information and references.

Examples

			a(1) = 22 because Kochański's first lower bound was 25/8 = A199657/A199658(1) and his first upper bound was 22/7 = a(1)/A199672(1).
a(2) = a(1) * (A191642(1) + 1) + 3 = 22*(15 + 1) + 3 = 352 + 3 = 355,
a(3) = a(2) * (A191642(2) + 1) + 3 = 355*(4697 + 1) + 3 = 1667793,
a(4) = a(3) * (A191642(3) + 1) + 3 = 1667793*(5548 + 1) + 3 = 9254583360.
		

Crossrefs

Programs

  • Mathematica
    g[x_, y_] = Floor[N[(Pi - 3)/(x - Pi*y), 200]];
    R = 22; S = 7;
    Reap[Print[R]; Sow[R]; For[i = 1, i <= 4, i++, b = g[R, S]; S = S*(b+1)+1; R = R*(b+1)+3; Print[R]; Sow[R]]][[2, 1]] (* Jean-François Alcover, Feb 21 2019 *)

Formula

a(1) = 22;
a(n) = a(n-1)*(A191642(n-1) + 1) + 3, where A191642 are Kochański's "genitores".

Extensions

More terms from Hugo Pfoertner, Mar 07 2020

A199672 Denominators of upper rational approximants of Pi with the first 5 terms given by Adam Adamandy Kochański in 1685, continued using a reconstruction by Fukś that is highly likely to match Kochański's incompletely published method.

Original entry on oeis.org

7, 113, 530875, 2945825376, 43524569930401, 1466647432944722498, 89572558672233037120355, 9963334846229825184971327361, 1155607355474812503904084375292947, 200867670528631909428607946113420047541, 113152173559177341323595142380773440920653498, 68570782937729264728805274258460609065120623055491
Offset: 1

Views

Author

Jonathan Vos Post, Nov 08 2011

Keywords

Comments

The corresponding numerators are given in A199671.
See A199657 for more information and references.

Examples

			a(1) = 7 because Kochański's first lower bound was 25/8 = A199657(1)/A199658(1) and his first upper bound was 22/7 = A199671(1)/a(1).
a(2) = a(1) * (A191642(1) + 1) + 1 = 7*(15 + 1) + 1 = 112 + 1 = 113,
a(3) = a(2) * (A191642(2) + 1) + 1 = 113*(4697 + 1) + 1 = 530875,
a(4) = a(3) * (A191642(3) + 1) + 1 = 530875*(5548 + 1) + 1 = 2945825376.
		

Crossrefs

Cf. A191642, A199657, A199658, A199671 (numerators).

Formula

a(1) = 7;
a(n) = a(n-1)*(A191642(n-1) + 1) + 1, where A191642 are Kochański's "genitores".

Extensions

More terms from Hugo Pfoertner, Mar 07 2020

A221706 Kochanski approximates to sqrt(2) starting with R_0=3, S_0=2.

Original entry on oeis.org

2, 4, 4, 15, 17, 77, 101, 119, 143, 250, 362, 1401, 31168, 88629, 184654, 259251, 298769, 4196069, 38538873, 616984562, 1975413034, 5345718056, 27843871196, 54516286512, 334398528973, 445879679625, 495957494385, 2450869042060, 2629541150528, 4088114099884
Offset: 0

Views

Author

N. J. A. Sloane, Jan 23 2013

Keywords

Crossrefs

Cf. A191642.

Programs

  • PARI
    galpha(alpha, R, S) = {floor((alpha - floor(alpha))/(R - alpha*S));}
    fuks() = { n = 29; default(realprecision, 200); alpha = sqrt(2); R = 3; S = 2; x = galpha(alpha, R, S); print1(x, ", "); for (i=1, n, R = R*(x+1) + floor(alpha); S = S*(x+1) + 1; x = galpha(alpha, R, S); print1(x, ", "););}
    \\ Michel Marcus, Feb 07 2013

Formula

Definitions 1 and 2 of Fuks (2011) give formulas.

Extensions

More terms from Michel Marcus, Feb 07 2013
Showing 1-5 of 5 results.