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 11 results. Next

A037008 Positions of the digit '0' in the decimal expansion of Pi, where positions 0, 1, 2, ... correspond to digits 3, 1, 4, ....

Original entry on oeis.org

32, 50, 54, 65, 71, 77, 85, 97, 106, 116, 121, 128, 132, 146, 159, 164, 167, 176, 195, 207, 245, 248, 264, 270, 287, 291, 307, 308, 311, 327, 330, 340, 357, 360, 361, 366, 369, 375, 398, 403, 408, 421, 443, 451, 493, 513, 520, 523, 543, 545, 552, 557, 561
Offset: 1

Views

Author

Nicolau C. Saldanha (nicolau(AT)mat.puc-rio.br)

Keywords

Examples

			Pi = 3.14159 26535 89793 23846 26433 83279 5*0*288 4... (Position 32 refers to the 32nd digit after the decimal point.)
		

Crossrefs

Cf. A000796 (decimal expansion (or digits) of Pi).
For another version see A014976(n) = a(n) + 1.
For digits 0 through 9 see: this sequence, A037000, A037001, A037002, A037003, A037004, A037005, A036974, A037006, A037007.

Programs

  • Mathematica
    Flatten @ Position[ RealDigits[Pi - 3, 10, 500][[1]], 0] (* Robert G. Wilson v, Mar 07 2011 *)
  • PARI
    for(c=1,default(realprecision,2011)-2,Pi\.1^c%10 || print1(c",")) \\ M. F. Hasler, Oct 23 2011
    
  • PARI
    A037008_upto(N=999)={localprec(N+20); [i-1|i<-[1..#N=digits(Pi\10^-N)],!N[i]]} \\ M. F. Hasler, Jul 29 2024

Formula

a(n) = A014976(n) - 1. - M. F. Hasler, Jul 29 2024

Extensions

Name edited by M. F. Hasler, Jul 29 2024

A096567 First digit to appear n times in the base-10 expansion of Pi.

Original entry on oeis.org

3, 1, 5, 3, 3, 3, 3, 3, 3, 9, 9, 9, 9, 9, 8, 8, 8, 8, 8, 8, 8, 8, 8, 2, 8, 8, 8, 8, 8, 8, 8, 8, 8, 4, 4, 4, 4, 4, 4, 8, 2, 2, 8, 2, 4, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Matthew Vandermast, Jun 26 2004

Keywords

Comments

The number 7 finally appears as a(32344). - T. D. Noe, Sep 13 2012
The number 6 appears for the first time as a(99032274). - Kester Habermann, Feb 01 2021

Examples

			a(3) = 5 because 5 is the first digit to appear 3 times in the decimal expansion of Pi = 3.141(5)926(5)3(5)... - _Bobby Jacobs_, Aug 30 2017
		

Crossrefs

Programs

  • Mathematica
    nn = 1000; t = {}; d = RealDigits[Pi, 10, nn][[1]]; dCnt = Table[0, {10}]; cnt = 1; Do[b = ++dCnt[[1 + d[[n]]]]; If[b == cnt, AppendTo[t, d[[n]]]; cnt++], {n, nn}]; t (* T. D. Noe, Sep 13 2012 *)

Extensions

More terms from David Wasserman, Nov 16 2007

A053745 Positions of '1's in the decimal expansion of Pi (where positions 1,2,3,... refer to the digits 3,1,4,...).

Original entry on oeis.org

2, 4, 38, 41, 50, 69, 95, 96, 104, 111, 139, 149, 154, 155, 156, 164, 169, 175, 176, 199, 207, 221, 239, 244, 247, 251, 270, 282, 296, 298, 315, 320, 325, 343, 345, 363, 364, 382, 386, 391, 394, 396, 397, 418
Offset: 1

Views

Author

Simon Plouffe, Feb 20 2000

Keywords

Crossrefs

Cf. A014976, A053746 - A053753 (the same for digits 0, ..., 9).
Cf. A088565 (primes in this sequence), A000796 (decimal digits of Pi).

Programs

  • Mathematica
    Flatten[Position[RealDigits[Pi, 10, 1000][[1]], 1]] (* Vincenzo Librandi, Oct 07 2013 *)
  • PARI
    A053745_upto(N=444, d=1)={localprec(N+20); [i|i<-[1..#N=digits(Pi\10^-N)], N[i]==d]} \\ M. F. Hasler, Jul 29 2024, replacing earlier code from 2017

Formula

a(n) = 1 + A037000(n), a variant where position 1 is the first digit after the decimal point. - M. F. Hasler, Mar 20 2017
a(n) ~ 10*n if Pi is normal (as generally assumed but yet unproved). - M. F. Hasler, Jul 29 2024

A088563 Primes p such that the p-th digit in the decimal expansion of Pi is 0.

Original entry on oeis.org

107, 271, 331, 367, 409, 521, 619, 683, 751, 839, 857, 997, 1013, 1117, 1123, 1361, 1439, 1483, 1489, 1601, 1607, 1609, 1747, 1831, 1889, 1913, 1999, 2131, 2137, 2251, 2341, 2671, 2819, 2887, 2957, 3011, 3019, 3169, 3203, 3253, 3299, 3331, 3407, 3413
Offset: 1

Views

Author

Cino Hilliard, Nov 19 2003

Keywords

Comments

The 9th zero in Pi is in the 107th place of the digits 3,1,4,1,5, ...

Crossrefs

Primes in A014976 (positions of '0's in decimal digits of Pi).
Cf. A088565 - A088566 (the same for digits 1 and 2), A000796 (decimal digits of Pi).

Programs

  • Mathematica
    With[{pidigs=RealDigits[Pi,10,10000][[1]]},Select[Prime[ Range[ 500]], pidigs[[#]]==0&]] (* Harvey P. Dale, Nov 13 2011 *)
  • PARI
    pizeros(n,d) = { default(realprecision,5000); p = Pi; v = Vec(Str(p)); for(x=1,n, if(v[x] == Str(d) && isprime(x-1),print1(x-1",")) ) }
    
  • PARI
    A088563_upto(N=3456)={localprec(N+20); [p|p<-primes([1, #N=digits(Pi\10^-N)]), !N[p]]} \\ M. F. Hasler, Jul 29 2024

A088565 Primes p such that the p-th digit in the decimal expansion of Pi is 1.

Original entry on oeis.org

2, 41, 139, 149, 199, 239, 251, 397, 433, 439, 443, 491, 569, 599, 641, 647, 661, 787, 853, 883, 1031, 1087, 1097, 1153, 1187, 1319, 1423, 1613, 1619, 1637, 1657, 1667, 1697, 1759, 1789, 2081, 2129, 2143, 2221, 2239, 2459, 2633, 2689, 2741, 2753, 2777
Offset: 1

Views

Author

Cino Hilliard, Nov 19 2003

Keywords

Examples

			The 1st digit 1 in Pi is in the 2nd place of the digits 3,1,4,1,5,9,..., and 2 is prime, whence a(1) = 2.  [Corrected and edited by _M. F. Hasler_, Jul 29 2024]
		

Crossrefs

Primes in A014976.
Cf. A088563, A088566 (the same for digits 0 and 2), A000796 (decimal digits of Pi).

Programs

  • Mathematica
    Select[Flatten[Position[RealDigits[Pi,10,2800][[1]],1]],PrimeQ] (* Harvey P. Dale, May 05 2019 *)
  • PARI
    pizeros(n,d) = { default(realprecision,5000); p = Pi; v = Vec(Str(p)); for(x=1,n, if(v[x] == Str(d) && isprime(x-1),print1(x-1",")) ) }
    
  • PARI
    A088565_upto(N=3456, d=1)={localprec(N+20); [p|p<-primes([1, #N=digits(Pi\10^-N)]), N[p]==d]} \\ M. F. Hasler, Jul 29 2024

A014974 Differences between successive locations of zeros in decimal expansion of Pi.

Original entry on oeis.org

18, 4, 11, 6, 6, 8, 12, 9, 10, 5, 7, 4, 14, 13, 5, 3, 9, 19, 12, 38, 3, 16, 6, 17, 4, 16, 1, 3, 16, 3, 10, 17, 3, 1, 5, 3, 6, 23, 5, 5, 13, 22, 8, 42, 20, 7, 3, 20, 2, 7, 5, 4, 35, 5, 1, 1, 15, 20, 19, 2, 10, 13, 2, 19, 12, 5
Offset: 1

Views

Author

Bagirath R. Krishnamachari (bagi(AT)callisto.miel.mot.com)

Keywords

Comments

Assuming Pi is normal, this sequence includes every finite sequence of positive integers. - Franklin T. Adams-Watters, Mar 15 2006

Examples

			First two 0's are in 33rd and 51st digits, difference is 18.
		

Crossrefs

Programs

  • Mathematica
    Differences[Flatten[Position[RealDigits[Pi,10,1000][[1]],0]]] (* Harvey P. Dale, Jul 04 2017 *)

Formula

a(n) = A014976(n+1) - A014976(n). - Michel Marcus, Oct 06 2013

Extensions

More terms from Simon Plouffe.

A096566 a(n) = concatenation of 10 distinct decimal digits in order of n-th appearance in the base-10 expansion of Pi.

Original entry on oeis.org

3145926870, 1539284670, 5932648170, 3295841670, 3289517460, 3958247160, 3945286017, 3942865107, 3928461057, 9382461057, 9832460517, 9832640517, 9823460517, 9823450167, 8293415067, 8923410567, 8239401567, 8249310567
Offset: 1

Views

Author

Matthew Vandermast, Jun 26 2004

Keywords

Comments

Maximal information-based nonparametric exploration statistical analysis program (MINE), which I applied "pairwise" to the first 62 terms, shows high values (up to 1) of the maximal information coefficient (MIC), which is a measure of two-variable dependence designed specifically for rapid exploration of many-dimensional data sets - see supplied links. - Alexander R. Povolotsky, Sep 07 2012
Computationally intractable question: what is the last term to appear, assuming all 9*9! terms eventually show up? - Charles R Greathouse IV, Sep 07 2012

Crossrefs

A349551 Rectangular array with ten rows, read by falling antidiagonals: row k gives positions of k in the decimal expansion (A000796) of Pi.

Original entry on oeis.org

33, 51, 2, 55, 4, 7, 66, 38, 17, 1, 72, 41, 22, 10, 3, 78, 50, 29, 16, 20, 5, 86, 69, 34, 18, 24, 9, 8, 98, 95, 54, 25, 37, 11, 21, 14, 107, 96, 64, 26, 58, 32, 23, 30, 12, 117, 104, 74, 28, 60, 49, 42, 40, 19, 6
Offset: 0

Views

Author

Clark Kimberling, Dec 17 2021

Keywords

Comments

Every positive integer occurs exactly once.
It is assumed that each digit occurs infinitely many times in A000796.

Examples

			(Base-10 digits of Pi) = (3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3, 8, 4, 6, 2, 6, 4, 3, 3, 8, 3, 2, 7, 9, 5, 0, ...); the position of the first 0 is 33, so the first term in row 0 is 33.
Corner:
  33, 51, 55, 66, 72, 78, 86, 98,  107,  117, 122, ... A014976
   2,  4, 38, 41, 50, 69, 95, 96,  104,  111, 139, ... A053745
   7, 17, 22, 29, 34, 54, 64, 74,   77,   84,  90, ... A053746
   1, 10, 16, 18, 25, 26, 28, 44,   47,   65,  87, ... A053747
   3, 20, 24, 37, 58, 60, 61, 71,   88,   93, 105, ... A053748
   5,  9, 11, 32, 49, 52, 62, 91,  110,  131, 132, ... A053749
   8, 21, 23, 42, 70, 73, 76, 83,   99,  109, 118, ... A053750
  14, 30, 40, 48, 57, 67, 97, 100, 121,  140, 157, ... A053751
  12, 19, 27, 35, 36, 53, 68, 75,   79,   82,  85, ... A053752
   6, 13, 15, 31, 39, 43, 45, 46,   56,   59,  63, ... A053753
		

Crossrefs

Cf. A000796, A014976, A053745-A053753, A032445 (includes column 1).

Programs

  • Mathematica
    r = RealDigits[Pi, 10, 200][[1]]
    t = Table[Flatten[Position[r, n]], {n, 0, 9}]
    TableForm[t]  (* A349551 array *)
    Flatten[Table[t[[n - k + 1, k]], {n, 10}, {k, n, 1, -1}]] (* A349551 sequence *)

A256109 Index of the n-th zero in the first occurrence of a string of exactly n zeros in the decimal expansion of Pi.

Original entry on oeis.org

33, 309, 604, 13394, 17539, 1699933, 3794579, 172330858, 2542542111, 8324296445, 371247087583, 1755524129985, 3186699229903, 6381820482345
Offset: 1

Views

Author

Kival Ngaokrajang, Mar 14 2015

Keywords

Comments

a(n) is the least k such that A000796(k-n+1) = ... = A000796(k) = 0 and A000796(k+1) != 0. - Danny Rorabaugh, Mar 31 2015

Crossrefs

Programs

  • PARI
    { default(realprecision, 20080); for (m = 1, 10, x = Pi; r = 0; for (n = 1, 20000, d = floor(x); x = (x-d)*10; if(d <> 0, if (r <> m, r = 0, print1(n-1, ", "); r = 0; break), r = r + 1)))}

Formula

a(n) = A050279(n) + n. - Danny Rorabaugh, Mar 31 2015

Extensions

a(6)-a(10) by Danny Rorabaugh, Mar 31 2015
a(11)-a(14) added using A050279 by Jinyuan Wang, Mar 30 2020

A329368 Partition the decimal expansion of Pi into non-overlapping strings of length 10: 3141592653, 5897932384,..; a(n) is the position of the strings where digits are different from each other.

Original entry on oeis.org

7, 548, 3113, 11665, 11728, 14305, 15762, 19177, 23288, 28259, 35603, 37613, 40595, 40740, 41477, 52108, 54085, 54367, 62272, 74856, 75082, 75178, 82919, 83591, 92284, 94936, 103849, 105419, 105832, 108875, 111962, 115152, 117919, 118976, 121112, 124121, 128505
Offset: 1

Views

Author

XU Pingya, Apr 27 2020

Keywords

Examples

			a(1) = 7, because such a string first occur at the 7th string: 4592307816 (i.e., 61-70 digits of Pi).
		

References

  • David Blatner, The Joy of Pi, Walker and Co., NY, 1997; page 91.

Crossrefs

Programs

  • Mathematica
    q[i_]:=q[i]=Take[RealDigits[Pi,10,10i][[1]],-10];
    a={}; Do[If[Length@Union@q[i]==10, AppendTo[a,i]], {i,130000}]
    a
Showing 1-10 of 11 results. Next