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 44 results. Next

A280532 a(1) = a(2) = 1, a(n) = A014777(a(n-1) + a(n-2)), n >= 3.

Original entry on oeis.org

1, 1, 6, 13, 37, 31, 605, 1411, 7174, 15567, 608953, 78903, 334535, 611552, 105928, 2557047, 2979162, 3263358, 6242520, 7825254, 37404834, 267494881, 639174488
Offset: 1

Views

Author

Anders Hellström, Jan 13 2017

Keywords

Crossrefs

Programs

  • Mathematica
    Module[{a = {1, 1}, s = First@ RealDigits[N[Pi, 10^7]]}, Do[AppendTo[a, -1 + SequencePosition[s, IntegerDigits[ a[[n - 1]] + a[[n - 2]] ]][[1, 1]]], {n, 3, 20}]; a] (* Michael De Vlieger, Jan 14 2017 *)

A134203 Duplicate of A014777.

Original entry on oeis.org

32, 1, 6, 9, 2, 4, 7, 13, 11, 5, 49, 94, 148, 110, 1, 3, 40, 95, 424, 37, 53, 93, 135, 16, 292, 89, 6, 28, 33, 186, 64, 137
Offset: 0

Views

Author

Keywords

A097614 In the decimal expansion of Pi, the string "0" is found at position 32 counting from the first digit after the decimal point. The string "32" is found at position 15, the string "15" at position 3, the string "3" at position 9, etc.

Original entry on oeis.org

0, 32, 15, 3, 9, 5, 4, 2, 6, 7, 13, 110, 174, 155, 314, 2120, 5360, 24671, 119546, 193002, 240820, 274454, 153700, 1397287, 17916598, 26245242, 8880928, 7320921, 14726415, 42969065, 35308126, 14978764, 68756682, 300921774
Offset: 0

Views

Author

Eric Angelini, Aug 30 2004

Keywords

Crossrefs

Cf. A014777.

Programs

Formula

a(0) = 0, a(1) = A014777(0) = 32, a(n) = A014777(a(n-1)), for n>1. - Anders Hellström, Jan 21 2017

Extensions

a(33) from Michael S. Branicky, Dec 05 2024

A176341 a(n) = the location of the first appearance of the decimal expansion of n in the decimal expansion of Pi.

Original entry on oeis.org

32, 1, 6, 0, 2, 4, 7, 13, 11, 5, 49, 94, 148, 110, 1, 3, 40, 95, 424, 37, 53, 93, 135, 16, 292, 89, 6, 28, 33, 186, 64, 0, 15, 24, 86, 9, 285, 46, 17, 43, 70, 2, 92, 23, 59, 60, 19, 119, 87, 57, 31, 48, 172, 8, 191, 130, 210, 404, 10, 4, 127, 219, 20, 312, 22, 7, 117, 98, 605, 41
Offset: 0

Views

Author

Daniel E. Loeb, Apr 15 2010

Keywords

Comments

It is unknown whether Pi is a normal number. If it is (at least in base 10) then this sequence is well defined.
The numbers a(n) refer to the position of the initial digit of n in the decimal expansion of Pi, where "3" is at position a(3)=0, "1" is at position a(1)=1, etc. This is also the numbering scheme used on the "Pi search page" cited among the LINKS. See A232013 for a sequence based on iterations of this one. See A032445 for a variant of the present sequence, where numbering starts at one. - M. F. Hasler, Nov 16 2013

Crossrefs

Programs

  • Mathematica
    p=ToString[FromDigits[RealDigits[N[Pi, 10^4]][[1]]]]; Do[Print[StringPosition[p, ToString[n]][[1]][[1]] - 1], {n, 0, 100}] (* Vincenzo Librandi, Apr 17 2017 *)
    With[{pid=RealDigits[Pi,10,800][[1]]},Flatten[Table[ SequencePosition[ pid,IntegerDigits[n],1],{n,0,70}],1]][[All,1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 27 2019 *)
  • PARI
    A176341(n)=my(L=#Str(n));n=Mod(n,10^L);for(k=L-1,9e9,Pi\.1^k-n||return(k+1-L)) \\ Make sure to use sufficient realprecision, e.g. via \p999. - M. F. Hasler, Nov 16 2013
  • Python
    pi = "314159265358979323846264338327950288419716939937510582097494459230..."
    [ pi.find(str(i)) for i in range(10000) ]
    

Formula

a(n) = A032445(n)-1. - M. F. Hasler, Nov 16 2013
a(n) = 0 if n is in A011545, otherwise a(n) = A014777(n). - Pontus von Brömssen, Aug 31 2024

A098266 a(1)=0; for i>=1, a(i+1)=position of first occurrence of a(i) in decimal expansion of e.

Original entry on oeis.org

0, 13, 27, 62, 32, 110, 3188, 12078, 141356, 2085932, 3497082, 4910326, 929922, 1189814, 4196683, 1301478, 19560712, 6894489, 41960008
Offset: 0

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 01 2004

Keywords

Comments

Recurrence sequence based on positions of digits in decimal places of e.

Examples

			So for example, a(2)=13 because 13th digit of e after decimal point is 0.
a(3)=27 because 27th decimal digit of e is 13, a(4)=62 because 62nd to 63rd decimal digits of e form "13" and so on.
		

Crossrefs

Cf. A078197 for the first occurrence of integers in decimal digits of e; A097614 for the analogous recurrence sequence for Pi, also A014777 for positions of integers in decimal digits of Pi.

Extensions

More terms from Ben Ross (bmr180(AT)psu.edu), Feb 01 2006

A134251 Positions of 1 after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

2, 10, 18, 41, 45, 50, 64, 65, 82, 97, 99, 101, 103, 113, 116, 133, 147, 170, 172, 175, 178, 191, 251, 252, 255, 265, 275, 285, 295, 297, 304, 329, 333, 340, 346, 350, 379, 385, 399, 410, 418, 432, 433, 443, 459, 473, 485, 493, 494, 509, 515, 519, 553, 558
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten @ Position[RealDigits[1/Pi, 10, 500][[1]], 1] (* Amiram Eldar, Mar 21 2020 *)

A134252 Positions of 2 after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

26, 32, 35, 43, 51, 73, 85, 86, 93, 102, 125, 129, 130, 131, 146, 183, 204, 212, 218, 229, 233, 241, 242, 260, 276, 277, 284, 309, 331, 332, 351, 357, 359, 389, 393, 403, 409, 425, 438, 447, 448, 458, 479, 482, 505, 534, 540, 550, 562, 564, 577, 581, 612, 620
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[Position[RealDigits[1/Pi,10,700][[1]],2]] (* Harvey P. Dale, Apr 22 2014 *)

A134253 Positions of 3 after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

1, 4, 12, 20, 58, 59, 69, 78, 92, 111, 120, 126, 136, 143, 150, 151, 164, 165, 186, 193, 197, 206, 211, 213, 214, 225, 234, 247, 254, 261, 267, 271, 288, 319, 342, 352, 353, 354, 364, 370, 373, 378, 384, 386, 387, 416, 421, 436, 439, 449, 452, 455, 457, 462
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[Position[RealDigits[1/Pi,10,500][[1]],3]] (* Harvey P. Dale, Sep 18 2013 *)

A134254 Positions of 4 after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

29, 36, 46, 55, 60, 76, 104, 109, 144, 148, 157, 160, 168, 176, 181, 196, 198, 205, 207, 219, 223, 226, 227, 237, 244, 245, 253, 272, 278, 301, 302, 316, 320, 321, 325, 338, 347, 372, 380, 391, 401, 426, 437, 456, 475, 498, 513, 523, 524, 527, 537, 542, 547
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten[Position[RealDigits[1/\[Pi] ,10,1000][[1]],4]]  (* Harvey P. Dale, Mar 20 2011 *)

A134255 Positions of 5 after decimal point in decimal expansion of 1/Pi.

Original entry on oeis.org

19, 25, 30, 57, 70, 72, 77, 90, 91, 94, 105, 108, 110, 112, 114, 123, 134, 138, 140, 141, 158, 173, 174, 179, 180, 188, 192, 201, 210, 230, 246, 250, 270, 291, 299, 324, 343, 360, 375, 382, 429, 431, 440, 450, 454, 465, 484, 490, 512, 517, 518, 529, 530, 531
Offset: 1

Views

Author

Artur Jasinski, Oct 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Flatten @ Position[RealDigits[1/Pi, 10, 500][[1]], 5] (* Amiram Eldar, Mar 21 2020 *)
Showing 1-10 of 44 results. Next