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 58 results. Next

A154134 Greatest number m such that the fractional part of (4/3)^A154130(n) <= 1/m.

Original entry on oeis.org

3, 6, 10, 30, 124, 238, 405, 6430, 22869, 32657, 224544, 2396968, 15229280, 28274047, 53458049, 134537968
Offset: 1

Views

Author

Hieronymus Fischer, Jan 11 2009

Keywords

Examples

			a(3)=10 since 1/11<fract((4/3)^A154130(3))=fract((4/3)^13)=0.09238...<=1/10.
		

Crossrefs

Formula

a(n):=floor(1/fract((4/3)^A154130(n))), where fract(x) = x-floor(x).

Extensions

a(12)-a(16) from Robert Price, May 10 2012

A153671 Minimal exponents m such that the fractional part of (101/100)^m obtains a maximum (when starting with m=1).

Original entry on oeis.org

1, 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, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 110, 180, 783, 859, 1803, 7591, 10763, 19105, 50172, 355146, 1101696, 1452050, 3047334, 3933030
Offset: 1

Views

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Recursive definition: a(1)=1, a(n) = least number m>a(n-1) such that the fractional part of (101/100)^m is greater than the fractional part of (101/100)^k for all k, 1<=k
The next such number must be greater than 10^6.
a(84) > 10^7. Robert Price, Mar 21 2019

Examples

			a(5)=5, since fract((101/100)^5)=0.05101005, but fract((101/100)^k)=0.01, 0.0201, 0.030301, 0.04060401 for 1<=k<=4; thus fract((101/100)^5)>fract((101/100)^k) for 1<=k<5.
		

Programs

  • Mathematica
    p = 0; Select[Range[1, 20000],
    If[FractionalPart[(101/100)^#] > p, p = FractionalPart[(101/100)^#];
    True] &] (* Robert Price, Mar 21 2019 *)
  • Python
    A153671_list, m, n, k, q = [], 1, 101, 100, 0
    while m < 10**4:
        r = n % k
        if r > q:
            q = r
            A153671_list.append(m)
        m += 1
        n *= 101
        k *= 100
        q *= 100 # Chai Wah Wu, May 16 2020

Formula

Recursion: a(1):=1, a(k):=min{ m>1 | fract((101/100)^m) > fract((101/100)^a(k-1))}, where fract(x) = x-floor(x).

Extensions

a(72)-a(83) from Robert Price, Mar 21 2019

A153669 Minimal exponents m such that the fractional part of (101/100)^m obtains a minimum (when starting with m=1).

Original entry on oeis.org

1, 70, 209, 378, 1653, 2697, 4806, 13744, 66919, 67873, 75666, 81125, 173389, 529938, 1572706, 4751419, 7159431, 7840546, 15896994, 71074288, 119325567
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Recursive definition: a(1)=1, a(n) = least number m>a(n-1) such that the fractional part of (101/100)^m is less than the fractional part of (101/100)^k for all k, 1<=k
The next term is greater than 2*10^8.

Examples

			a(2)=70, since fract((101/100)^70)=0.00676..., but fract((101/100)^k)>=0.01 for 1<=k<=69; thus fract((101/100)^70)<fract((101/100)^k) for 1<=k<70.
		

Programs

  • Mathematica
    p = 1; Select[Range[1, 5000],
    If[FractionalPart[(101/100)^#] < p, p = FractionalPart[(101/100)^#];
    True] &] (* Robert Price, Mar 21 2019 *)

Formula

Recursion: a(1):=1, a(k):=min{ m>1 | fract((101/100)^m) < fract((101/100)^a(k-1))}, where fract(x) = x-floor(x).

Extensions

a(15)-a(21) from Robert Gerbicz, Nov 22 2010

A153670 Numbers k such that the fractional part of (101/100)^k is less than 1/k.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 70, 209, 241, 378, 2697, 4806, 173389, 529938, 1334508, 1572706, 7840546, 15896994, 20204295, 71074288, 119325567
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Numbers k such that fract((101/100)^k) < 1/k, where fract(x) = x-floor(x).
The next term is greater than 2*10^8.

Examples

			a(10) = 70 since fract((101/100)^70) = 0.006... < 1/10, but fract((101/100)^k) > 0.1 >= 1/k for 10 <= k <= 69.
		

Programs

  • Mathematica
    Select[Range[1000], FractionalPart[(101/100)^#] < (1/#) &] (* G. C. Greubel, Aug 24 2016 *)
  • Python
    from itertools import count, islice
    def A153670gen(): # generator of terms
        k10, k11 = 100, 101
        for k in count(1):
            if (k11 % k10)*k < k10:
                yield k
            k10 *= 100
            k11 *= 101
    A153670_list = list(islice(A153670gen(),16)) # Chai Wah Wu, Dec 23 2021

Extensions

a(18)-a(24) from Robert Gerbicz, Nov 29 2010

A153672 Numbers k such that the fractional part of (101/100)^k is greater than 1-(1/k).

Original entry on oeis.org

1, 69, 180, 783, 859, 1803, 10763, 19105, 39568, 50172, 132572, 355146, 1452050, 2245950, 3047334, 3933030, 4165171, 98544173
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Numbers k such that fract((101/100)^k) > 1-(1/k), where fract(x) = x-floor(x).
The next term is greater than 2*10^8.

Examples

			a(2) = 69, since fract((101/100)^69) = 0.9868... > 0.9855... = 1 - (1/69), but fract((101/100)^k) <= 1 - (1/k) for 1 < k < 69.
		

Programs

  • Mathematica
    Select[Range[1000], FractionalPart[(101/100)^#] >= 1 - (1/#) &] (* G. C. Greubel, Aug 24 2016 *)

Extensions

a(13)-a(18) from Robert Gerbicz, Nov 22 2010

A137994 a(n) is the smallest integer > a(n-1) such that {Pi^a(n)} < {Pi^a(n-1)}, where {x} = x - floor(x), a(1)=1.

Original entry on oeis.org

1, 3, 81, 264, 281, 472, 1147, 2081, 3207, 3592, 10479, 12128, 65875, 114791, 118885
Offset: 1

Author

Leroy Quet and M. F. Hasler, Mar 14 2008

Keywords

Comments

The sequence was suggested by Leroy Quet on Pi day 2008, cf. A138324.
The next such number must be greater than 100000. - Hieronymus Fischer, Jan 06 2009
a(16) > 300,000. - Robert Price, Mar 25 2019

Examples

			a(3)=81, since {Pi^81}=0.0037011283.., but {Pi^k}>=0.0062766802... for 1<=k<=80; thus {Pi^81}<{Pi^k} for 1<=k<81. - _Hieronymus Fischer_, Jan 06 2009
		

Programs

  • Mathematica
    $MaxExtraPrecision = 10000;
    p = .999;
    Select[Range[1, 5000],
    If[FractionalPart[Pi^#] < p, p = FractionalPart[Pi^#]; True] &] (* Robert Price, Mar 12 2019 *)
  • PARI
    default(realprecision,10^4); print1(a=1); for(i=1,100, f=frac(Pi^a); until( frac(Pi^a++)
    				

Extensions

a(11)-a(13) from Hieronymus Fischer, Jan 06 2009
Edited by R. J. Mathar, May 21 2010
a(14)-a(15) from Robert Price, Mar 12 2019

A153677 Minimal exponents m such that the fractional part of (1024/1000)^m obtains a minimum (when starting with m=1).

Original entry on oeis.org

1, 68, 142, 341, 395, 490, 585, 1164, 1707, 26366, 41358, 46074, 120805, 147332, 184259, 205661, 385710, 522271, 3418770, 3675376, 9424094
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Recursive definition: a(1)=1, a(n) is the least positive integer m such that the fractional part of (1024/1000)^m is less than the fractional part of (1024/1000)^k for all k, 1 <= k < m.
a(21) >= 4.5*10^6. - David A. Corneth, Mar 15 2019
a(22) > 10^7. Robert Price, Mar 16 2019

Examples

			a(2)=68, since fract((1024/1000)^68) = 0.016456..., but fract((1024/1000)^k) >= 0.024 for 1 <= k <= 67; thus fract((1024/1000)^68) < fract((1024/1000)^k) for 1 <= k < 68.
		

Programs

  • Mathematica
    $MaxExtraPrecision = 10000;
    p = .999;
    Select[Range[1, 50000],
    If[FractionalPart[(1024/1000)^#] < p,
    p = FractionalPart[(1024/1000)^#]; True] &] (* Robert Price, Mar 15 2019 *)
  • PARI
    upto(n) = my(res = List(), r = 1, p = 1); for(i=1, n, c = frac(p *= 1.024); if(cDavid A. Corneth, Mar 15 2019

Formula

Recursion: a(1):=1, a(k):=min{ m>1 | fract((1024/1000)^m) < fract((1024/1000)^a(k-1))}, where fract(x) = x-floor(x).

Extensions

a(18) from Robert Price, Mar 15 2019
a(19)-a(20) from David A. Corneth, Mar 15 2019
a(21) from Robert Price, Mar 16 2019

A153678 Numbers k such that the fractional part of (1024/1000)^k is less than 1/k.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 585, 1164, 1707, 522271, 3675376, 3906074, 9424094
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Numbers k such that fract((1024/1000)^k) < 1/k, where fract(x) = x-floor(x).
The next such number must be greater than 5*10^5.
a(14) > 10^7. - Robert Price, Mar 16 2019

Examples

			a(7) = 585 since fract((1024/1000)^585) = 0.00139... < 1/585, but fract((1024/1000)^k) >= 1/k for 7 <= k <= 584.
		

Programs

  • Mathematica
    Select[Range[2000], FractionalPart[(1024/1000)^#] < (1/#) &] (* G. C. Greubel, Aug 24 2016; corrected by Robert Price, Mar 16 2019 *)
  • PARI
    isok(n) = frac((1024/1000)^n) < 1/n \\ Michel Marcus, Aug 06 2013

Extensions

a(10)-a(13) from Robert Price, Mar 16 2019

A153679 Minimal exponents m such that the fractional part of (1024/1000)^m obtains a maximum (when starting with m=1).

Original entry on oeis.org

1, 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, 82, 134, 1306, 2036, 6393, 34477, 145984, 2746739, 2792428, 8460321
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Recursive definition: a(1)=1, a(n) = least number m>a(n-1) such that the fractional part of (1024/1000)^m is greater than the fractional part of (1024/1000)^k for all k, 1<=k
The next such number must be greater than 5*10^5.
a(40) > 10^7. Robert Price, Mar 16 2019

Examples

			a(30)=82, since fract((1024/1000)^82)= 0.99191990..., but fract((1024/1000)^k)<0.9893 for 1<=k<=81; thus fract((1024/1000)^82)>fract((1024/1000)^k) for 1<=k<82 and 82 is the minimal exponent >29 with this property.
		

Programs

  • Mathematica
    $MaxExtraPrecision = 10000;
    p = 0;
    Select[Range[1, 50000],
    If[FractionalPart[(1024/1000)^#] > p,
    p = FractionalPart[(1024/1000)^#]; True] &] (* Robert Price, Mar 16 2019 *)
  • Python
    A153679_list, m, n, k, q = [], 1, 1024, 1000, 0
    while m < 10**4:
        r = n % k
        if r > q:
            q = r
            A153679_list.append(m)
        m += 1
        n *= 1024
        k *= 1000
        q *= 1000 # Chai Wah Wu, May 16 2020

Formula

Recursion: a(1):=1, a(k):=min{ m>1 | fract((1024/1000)^m) > fract((1024/1000)^a(k-1))}, where fract(x) = x-floor(x).

Extensions

a(37)-a(39) from Robert Price, Mar 16 2019

A153680 Numbers k such that the fractional part of (1024/1000)^k is greater than 1-(1/k).

Original entry on oeis.org

1, 29, 82, 134, 277, 1306, 2036, 2349, 6393, 9389, 9816, 21689, 34477, 145984, 171954, 956357, 2746739
Offset: 1

Author

Hieronymus Fischer, Jan 06 2009

Keywords

Comments

Numbers k such that fract((1024/1000)^k) > 1-(1/k), where fract(x) = x-floor(x).
The next such number must be greater than 5*10^5.

Examples

			a(2) = 29, since fract((1024/1000)^29) = 0.98929... > 0.9655... = 1 - (1/29), but fract((1024/1000)^k) <= 1 - (1/k) for 1 < k < 29.
		

Programs

  • Mathematica
    Select[Range[1000], FractionalPart[(1024/1000)^#] >= 1 - (1/#) &] (* G. C. Greubel, Aug 24 2016 *)

Extensions

a(16)-a(17) from Hagen von Eitzen, May 16 2009
Showing 1-10 of 58 results. Next