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.

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A128050 Position of start of first occurrence of prime(n) after the decimal point in expansion of golden ratio phi.

Original entry on oeis.org

19, 5, 22, 10, 34, 55, 35, 188, 131, 174, 137, 98, 90, 27, 102, 111, 166, 1, 150, 217, 479, 44, 25, 13, 81, 458, 1242, 744, 563, 96, 1602, 186, 97, 995, 259, 939, 1999, 1204, 641, 1191, 43, 833, 1682, 2833, 2708, 188, 647, 130, 62, 734, 2337, 1106, 307, 1156, 2532
Offset: 1

Views

Author

Gregory Allen, Feb 13 2007

Keywords

Examples

			Golden ratio phi = 1.6180339887498948482045868343656381177... (see A001622).
First occurrence of prime(1) = 2 is at the 19th digit after the decimal point, hence a(1) = 19.
First occurrence of prime(5) = 11 starts at the 34th digit after the decimal point, hence a(5) = 34.
		

Crossrefs

Programs

  • Magma
    k:=3000; R := RealField(k); [ Position(IntegerToString(Round(10^k*(-1 + (Sqrt(elt)+1) / elt))), IntegerToString(NthPrime(n))) : n in [1..55] ]; /* Klaus Brockhaus, Feb 15 2007 */
  • Mathematica
    Module[{p = Rest[First[RealDigits[GoldenRatio, 10, 10^4]]], n = 0, a}, Reap[While[(a = SequencePosition[p, IntegerDigits[Prime[++n]], 1]) != {}, Sow[a[[1, 1]]]]][[2, 1]]] (* Paolo Xausa, Aug 01 2024 *)

Extensions

Edited, corrected and extended by Klaus Brockhaus, Feb 15 2007

A133268 a(n) = positions of 0's after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

5, 15, 31, 37, 48, 79, 81, 84, 89, 95, 118, 137, 189, 222, 232, 240, 258, 264, 269, 279, 298, 314, 315, 362, 371, 394, 435, 451, 460, 463, 466, 472, 480, 497, 507, 510, 520, 521, 525, 541, 565, 569, 571, 596, 600, 606, 609, 610, 636, 670, 702, 703, 706, 707
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[Position[RealDigits[1/Pi,10,1000][[1]],0]] (* Harvey P. Dale, May 16 2012 *)

A134210 Positions of 10 after the decimal point in the decimal expansion of Pi.

Original entry on oeis.org

49, 163, 175, 206, 269, 442, 681, 780, 852, 854, 1011, 1219, 1223, 1270, 1318, 1487, 1816, 1892, 2162, 2238, 2514, 2534, 2563, 2721, 2749, 2780, 2810, 2874, 2880, 2955, 3170, 3201, 3208, 3241, 3254, 3405, 3457, 3480, 3486, 3494, 3845, 3848, 3939, 3964, 3966
Offset: 1

Views

Author

Artur Jasinski, Oct 14 2007

Keywords

Crossrefs

Programs

  • Mathematica
    SequencePosition[RealDigits[Pi,10,10000][[1]],{1,0}][[All,1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 20 2016 *)

Extensions

More terms from Harvey P. Dale, Nov 20 2016

A256521 Table T(n, k) of positions p[i] where number n occurs after the decimal point in the decimal expansion of Pi, read by antidiagonals.

Original entry on oeis.org

32, 50, 1, 54, 3, 6, 65, 37, 16, 9, 71, 40, 21, 15, 2, 77, 49, 28, 17, 19, 4, 85, 68, 33, 24, 23, 8, 7, 97, 94, 53, 25, 36, 10, 20, 13, 106, 95, 63, 27, 57, 31, 22, 29, 11, 116, 103, 73, 43, 59, 48, 41, 39, 18, 5, 121, 110, 76, 46, 60, 51, 69, 47, 26, 12, 49, 128, 138, 83, 64, 70, 61, 72, 56, 34, 14, 163, 94
Offset: 0

Views

Author

Felix Fröhlich, Apr 01 2015

Keywords

Comments

Table T(n, k) starts:
n = 0: 32, 50, 54, 65, 71, 77, 85, 97, 106, 116, ...
n = 1: 1, 3, 37, 40, 49, 68, 94, 95, 103, 110, ...
n = 2: 6, 16, 21, 28, 33, 53, 63, 73, 76, 83, ...
n = 3: 9, 15, 17, 24, 25, 27, 43, 46, 64, 86, ...
n = 4: 2, 19, 23, 36, 57, 59, 60, 70, 87, 92, ...
n = 5: 4, 8, 10, 31, 48, 51, 61, 90, 109, 130, ...
n = 6: 7, 20, 22, 41, 69, 72, 75, 82, 98, 108, ...
n = 7: 13, 29, 39, 47, 56, 66, 96, 99, 120, 139, ...
n = 8: 11, 18, 26, 34, 35, 52, 67, 74, 78, 81, ...
n = 9: 5, 12, 14, 30, 38, 42, 44, 45, 55, 58, ...
n = 10: 49, 163, 175, 206, 269, 442, 681, 780, 852, 854, ...
...

Examples

			T(6, 4) = 41, since the fourth occurrence of 6 in the decimal expansion of Pi is at position 41.
		

Crossrefs

Cf. A000796 (Pi), A014777 (first column).
Cf. A037008, A037000, A037001, A037002, A037003 (0th to 4th row).
Cf. A037004, A037005, A036974, A037006, A037007 (5th to 9th row).

Programs

  • Mathematica
    spi = StringDrop[ ToString[ N[ Pi, 1000]], 2]; t[n_, k_] := StringPosition[ spi, ToString[n], k][[-1, 1]]; Table[ t[n - k, k], {n, 0, 12}, {k, n, 1, -1}] // Flatten (* Robert G. Wilson v, Apr 07 2015 *)

Extensions

More terms from Robert G. Wilson v, Apr 07 2015

A332929 Position where the binary expansion of n occurs for the first time in the binary expansion of Pi.

Original entry on oeis.org

3, 1, 2, 1, 2, 18, 1, 13, 8, 2, 21, 18, 1, 17, 16, 13, 8, 27, 2, 62, 25, 21, 18, 93, 49, 1, 20, 17, 95, 16, 15, 13, 97, 8, 27, 45, 2, 128, 62, 146, 25, 60, 21, 395, 229, 18, 93, 209, 49, 65, 1, 78, 42, 20, 17, 105, 95, 116, 186, 16, 175, 15, 14, 13, 97, 110
Offset: 0

Views

Author

Thomas König, Mar 02 2020

Keywords

Examples

			In binary, Pi = 11.00100100.... The bitstring 10 (for 2) occurs at position 2, so a(2) = 2.
		

Crossrefs

Cf. A032445 (for decimal expansion rather than binary).

Programs

  • Mathematica
    p = RealDigits[Pi,2,500][[1]]; L = {}; Do[t = SequencePosition[p, IntegerDigits[n, 2], 1]; If[t == {}, Break[], AppendTo[L, t[[1, 1]]]], {n, 0, 65}]; L (* Giovanni Resta, Mar 16 2020 *)
    Module[{nn=500,bp},bp=RealDigits[Pi,2,nn][[1]];Table[ SequencePosition[ bp,IntegerDigits[n,2],1][[All,1]],{n,0,70}]]//Flatten (* Harvey P. Dale, Sep 18 2021 *)
  • Perl
    #! /usr/bin/perl
    # Feed b004601.txt to this to get the binary digits of Pi.
    while (<>) {
        chomp;
        (undef, $d[$n++]) = split(" ");
    }
    $pi = join("",@d);
    $k = 0;
    while (1) {
        last if ($pos = index($pi, sprintf("%b", $k++))) < 0;
        $out .= $pos +2 . ", ";
    }
    print $out,"\n";

A038101 First location of palindrome a(n) in decimal expansion of Pi is palindromic.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 99, 141, 151, 313, 343, 505, 535, 585, 767, 959, 1771, 6446, 9669, 15751, 32823, 39193, 48184, 59995, 65456, 73137, 85858, 323323, 944449, 1081801, 1155511, 1299921, 1491941, 5514155, 5870785, 7639367, 7913197, 7940497, 8156518, 8257528
Offset: 1

Views

Author

Patrick De Geest, Feb 15 1999

Keywords

Comments

'Location' starts from the first digit after the decimal point and refers to the first digit of the palindrome.

Crossrefs

Extensions

Offset changed to 1 by and more terms from Jinyuan Wang, Sep 04 2021

A061073 First occurrence of n consecutive n's in the decimal expansion of Pi.

Original entry on oeis.org

1, 135, 1698, 54525, 24466, 252499, 3346228, 46663520, 564665206
Offset: 1

Views

Author

Jason Earls, May 27 2001

Keywords

Examples

			1 first occurs at position 1 after the decimal point.
22 first occurs at position 135.
333 first occurs at position 1698.
10101010101010101010 does not occur in the first 1.1*10^10 digits of Pi - _Eric W. Weisstein_, Jul 19 2013
		

Crossrefs

Cf. A014777.

Extensions

a(9) from Eric W. Weisstein, Jan 16 2006
Entry revised by Don Reble, Apr 06 2006

A082591 Starting position of the first occurrence of n in the decimal expansion of Pi such that a(n) > a(n-1) for n >= 1.

Original entry on oeis.org

32, 37, 53, 64, 70, 90, 98, 99, 101, 122, 163, 174, 220, 281, 295, 314, 396, 428, 446, 495, 600, 650, 661, 698, 803, 822, 841, 977, 1090, 1124, 1358, 1435, 1501, 1667, 1668, 1719, 1828, 1926, 1968, 1987, 2007, 2161, 2210, 2236, 2261, 2305, 2416, 2509, 2555
Offset: 0

Views

Author

Rick L. Shepherd, May 13 2003

Keywords

Comments

a(m)=c means that c + digit_length(m) - 1 is the minimal number of decimal digits of Pi after the decimal point containing all m+1 digit strings 0, 1, 2, ..., m in increasing order from left-to-right (with intervening digit strings of course) - but with some strings overlapping if m >= 34. a(10)=163 ==> 163+2-1=164 digits are necessary to contain in the 11 strings 0, 1, 2, ..., 10 in order.

Examples

			a(0) = 32, the position of the first 0 in the decimal expansion of Pi.
a(1) = 37, the position of the first 1 after the first 0.
a(33) = 1667, the starting position of the first string 33 such that
a(33) > a(32)=1501. a(34) = 1668, the starting position of the first string 34
such that a(34) > a(33)=1667. Note that these occurrences of 33 and 34 overlap.
		

Crossrefs

Cf. A014777 (position of first n).

A100080 Position of first occurrence of n after the decimal point in the decimal expansion of 1/Pi.

Original entry on oeis.org

5, 2, 26, 1, 29, 19, 9, 13, 3, 6, 297, 64, 50, 385, 45, 18, 116, 65, 2, 41, 393, 102, 85, 125, 35, 93, 26, 86, 32, 43, 4, 1, 92, 58, 59, 69, 126, 12, 165, 151, 36, 717, 437, 196, 226, 29, 60, 160, 46, 55, 30, 112, 25, 19, 108, 90, 105, 134, 123, 70, 88, 9, 446, 149, 236, 511
Offset: 0

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 03 2004

Keywords

Comments

a(0) = A133268(1),
a(1) = A134251(1),
a(2) = A134252(1),
a(3) = A134253(1),
a(4) = A134254(1),
a(5) = A134255(1),
a(6) = A134256(1),
a(7) = A134257(1),
a(8) = A134258(1),
a(9) = A134259(1),
a(10) = A134260(1). - Artur Jasinski, Oct 16 2007

Examples

			1/Pi = 0.31830988618379067153776752674... so the first occurrence of 0 after the decimal point is at position 5; first occurrence of 1 is at position 2; first occurrence of 2 is at position 26; etc.
		

Crossrefs

Programs

  • Mathematica
    Table[ SequencePosition[#, IntegerDigits@ n][[1, 1]], {n, 0, 65}] &@ First@ RealDigits@ N[1/Pi, 10^4] (* James C. McMahon, Feb 06 2024 *)

Extensions

Edited by N. J. A. Sloane, Jun 30 2008 at the suggestion of R. J. Mathar

A101196 Position of n-th n after the decimal point in Pi.

Original entry on oeis.org

1, 16, 17, 36, 48, 72, 96, 74, 55, 854, 709, 1080, 1076, 1636, 1657, 1651, 889, 1674, 1227, 2039, 1486, 2372, 2690, 2288, 2033, 2282, 1785, 2703, 4155, 3102, 3584, 3767, 4325, 3808, 3551, 4081, 3785, 3229, 4464, 4884, 4127, 4228, 5336, 3961, 4242, 3633
Offset: 1

Views

Author

Michael Joseph Halm, Dec 12 2004

Keywords

Examples

			a(2) = 16 because the second occurrence of 2 in the digits of pi after its decimal point is at position 16, that is, after 141592653589793.
		

Crossrefs

Extensions

Corrected and extended by Mark Hudson (mrmarkhudson(AT)hotmail.com), Dec 13 2004
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