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 13 results. Next

A037001 Positions of the digit '2' in the decimal expansion of Pi (where positions 0, 1, 2,... refer to the digits 3, 1, 4,...).

Original entry on oeis.org

6, 16, 21, 28, 33, 53, 63, 73, 76, 83, 89, 93, 102, 112, 114, 135, 136, 140, 149, 160, 165, 173, 185, 186, 203, 221, 229, 241, 244, 260, 275, 280, 289, 292, 298, 302, 326, 329, 333, 335, 337, 354, 374, 380, 406, 423, 435, 456, 462, 477, 479, 484, 485, 500
Offset: 1

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Author

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

Keywords

Comments

The first few primes in this sequence are 53, 73, 83, 89, 149, 173, 229, 241, 337, 479, 571, 613, 661, 757, 829, 877, 911, 977, 991, ... - M. F. Hasler, Jul 28 2024

Crossrefs

Cf. A000796 (decimal expansion (or digits) of Pi).
Cf. A053746 (= a(n) + 1: the same with different offset).
Cf. A037000, A037002, A037003, A037004, A037005, A036974, A037006, A037007, A037008 (similar for digits 1, ..., 9 and 0).
Cf. A035117 (first occurrence of at least n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
Cf. A096755 (first occurrence of exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
Cf. A121280 = A068987 - 1: position of "123...n" in Pi's decimals.
Cf. A176341: first occurrence of n in Pi's digits.

Programs

  • Mathematica
    Flatten @ Position[ RealDigits[Pi - 3, 10, 500][[1]], 2] (* Robert G. Wilson v, Mar 07 2011 *)
  • PARI
    A037001_upto(N=999, d=2)={localprec(N+20); [i-1|i<-[1..#N=digits(Pi\10^-N)], N[i]==d]} \\ M. F. Hasler, Jul 28 2024

Formula

a(n) ~ 10*n if Pi is normal, as generally assumed. - M. F. Hasler, Jul 28 2024

A096763 Position of the first occurrence of exactly n consecutive '9's in a row in the decimal expansion of Pi.

Original entry on oeis.org

5, 44, 2949, 17988, 19446, 762, 1722776, 36356642, 564665206, 20148132310, 27014073304, 897831316556, 10542036048450, 5758910552709
Offset: 1

Views

Author

Robert G. Wilson v, Jul 07 2004

Keywords

Crossrefs

Cf. A000796: Decimal expansion (or digits) of Pi.
First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
First occurrence of n: A176341; of concatenate(1,...,n): A121280 = A068987 - 1.

Extensions

a(10)-a(11) from Giovanni Resta, Sep 30 2019
a(12) from Yasumasa Kanada, 2002 and a(13)-a(14) from Shigeru Kondo, 2011, added by Dmitry Petukhov, Dec 27 2019

A035117 a(n) is the starting position of the first occurrence of a string of at least n 1's in the decimal expansion of Pi.

Original entry on oeis.org

1, 94, 153, 12700, 32788, 255945, 4657555, 159090113, 812432526, 3961184001, 15647738228, 1041032609981, 3907688331257, 68635742334547
Offset: 1

Views

Author

Leonardo Bitran (lbitran(AT)reuna.cl)

Keywords

Comments

Presently identical to A096755, which is the first occurrences of exactly n 1's in the digits of Pi. Will differ as soon as there's some a(n) = a(n+1) and equivalently, A035117(n) > A035117(n+1). - M. F. Hasler, Mar 17 2017

Crossrefs

Cf. A000796 (decimal expansion (or digits) of Pi).
Cf. A035117 (this), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
Cf. A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
Cf. A121280 = A068987 - 1 (position of "123...n" in Pi's decimals).
Cf. A176341 (first occurrence of n in Pi's digits).

Extensions

More terms from Colin Martin (cbmartin(AT)tpg.com.au), Mar 03 2002
Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, May 27 2007
Edited, after re-establishing A096755, by M. F. Hasler, Mar 17 2017
a(11) from Giovanni Resta, Sep 30 2019
a(12) from Yasumasa Kanada Laboratory, 2002 and a(13) from Shigeru Kondo, 2011, added by Dmitry Petukhov, Dec 27 2019
a(14) from Dmitry Petukhov, Sep 19 2022

A048940 Starting position of the first occurrence of a string of at least n '9's in the decimal expansion of Pi.

Original entry on oeis.org

5, 44, 762, 762, 762, 762, 1722776, 36356642, 564665206, 20148132310, 27014073304, 897831316556, 5758910552709, 5758910552709
Offset: 1

Views

Author

Keywords

Comments

a(10) > 11*10^9 - 1. - Eric W. Weisstein, Jul 20 2013
a(15) > 22*10^12. - Dmitry Petukhov, Jan 29 2020
Pi digits 3,1,4,... are indexed 0,1,2,... Note that this is different from other sequences such as A049522, A084073 which use indices 1,2,3,... For example, the position of the curious accumulation of six 9s is called 762 here; the same position is called 763 in A049522, A084073. - Jeppe Stig Nielsen, Aug 21 2017

Crossrefs

Cf. A000796: Decimal expansion (or digits) of Pi.
First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
First occurrence of n: A176341; of concatenate(1,...,n): A121280 = A068987 - 1.

Programs

  • Mathematica
    Module[{m, nn = 7}, m = First@ RealDigits@ N[Pi, 10^nn]; Array[ SequencePosition[m, ConstantArray[9, #]][[1, 1]] - 1 &, nn]] (* Michael De Vlieger, Mar 20 2017 *)

Extensions

More terms from Colin Martin (cbmartin(AT)tpg.com.au), Mar 03 2002
Edited by M. F. Hasler, Mar 19 2017
a(10)-a(11) from Giovanni Resta, Sep 30 2019
a(12) from Yasumasa Kanada Laboratory, 2002 and a(13)-a(14) from Shigeru Kondo, 2011 added by Dmitry Petukhov, Dec 23 2019

A050279 a(n) is the starting position of the first occurrence of a string of at least n '0's in the decimal expansion of Pi.

Original entry on oeis.org

32, 307, 601, 13390, 17534, 1699927, 3794572, 172330850, 2542542102, 8324296435, 371247087572, 1755524129973, 3186699229890, 6381820482331
Offset: 1

Views

Author

Keywords

Comments

At least up to a(10), also the starting position of the first occurrence of a string of exactly n '0's in the decimal expansion of Pi, cf. A096764. - M. F. Hasler, Mar 19 2017, edited Sep 03 2017
a(15) > 22*10^12. - Dmitry Petukhov, Jan 28 2020

References

  • Shigeru Kondo, calculation of Pi to 12.8 * 10^9 digits, using the program PiFast of Xavier Gourdon

Crossrefs

See A096764 for another version.
Cf. A000796: Decimal expansion (or digits) of Pi.
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A096764 (exactly n '0's).
First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of concatenate(1,...,n): A121280 = A068987 - 1.

Extensions

More terms from Colin B. Martin (martinc(AT)ram.net.au), Nov 25 2001
Edited by N. J. A. Sloane at the suggestion of M. F. Hasler, Aug 24 2007
Edited by M. F. Hasler, Mar 19 2017
Definition modified by N. J. A. Sloane, Sep 03 2017
a(11)-a(14) added by Dmitry Petukhov, Jan 12 2020

A096761 Position of first occurrence of exactly n consecutive sevens in a row in the decimal expansion of Pi.

Original entry on oeis.org

13, 559, 4575, 1589, 162248, 399579, 3346228, 82144203, 24658601, 22869046249, 165431035708, 368299898266, 10541103245815, 14793486898235, 46970519777308
Offset: 1

Views

Author

Robert G. Wilson v, Jul 07 2004

Keywords

Comments

Differs from A050286 from a(3) > a(4) on. - M. F. Hasler, Mar 18 2017
a(11) > 99*10^9. - Giovanni Resta, Oct 02 2019
a(15) > 22*10^12. - Dmitry Petukhov, Jan 27 2020
a(16) > 50*10^12. - Dmitry Petukhov, Oct 30 2021

Crossrefs

First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
First occurrence of n: A176341; of concatenate(1,...,n): A121280 = A068987 - 1.
Cf. A000796 (decimal expansion (or digits) of Pi).

Extensions

Edited by M. F. Hasler, Mar 19 2017
a(10) from Giovanni Resta, Oct 02 2019
a(11)-a(13) added by Dmitry Petukhov, Jan 13 2020
a(14) from Dmitry Petukhov, Jan 27 2020
a(15) from Dmitry Petukhov, Oct 30 2021

A096762 Position of first occurrence of exactly n consecutive '8's in a row in the decimal expansion of Pi.

Original entry on oeis.org

11, 34, 4985, 4751, 213245, 222299, 4722613, 239798471, 46663520, 3040319543, 159999448572, 1141385905180, 2164164669332, 91250566353705
Offset: 1

Views

Author

Robert G. Wilson v, Jul 07 2004

Keywords

Comments

a(8) > 2*10^8, a(9) = 46663520, a(10) = 3040319543.
Differs from A050287 from a(3) > A050287(3) = A050287(4) = a(4) on. - M. F. Hasler, Mar 19 2017

Crossrefs

Cf. A000796: Decimal expansion (or digits) of Pi.
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of concatenate(1,...,n): A121280 = A068987 - 1.

Extensions

Edited by M. F. Hasler, Mar 19 2017
a(8) via SubIdiom.com/pi search engine from M. F. Hasler, Apr 13 2019
a(11)-a(13) added by Dmitry Petukhov, Dec 30 2019
a(14) from Dmitry Petukhov, Sep 20 2022

A096757 Index of first occurrence of exactly n consecutive threes in a row in the decimal expansion of Pi.

Original entry on oeis.org

9, 24, 1698, 66846, 28467, 1129019, 710100, 36488176, 2011485307, 4663739959, 60422218263, 1379574176590, 26258139334603
Offset: 1

Views

Author

Robert G. Wilson v, Jul 07 2004

Keywords

Comments

Differs from A050282 as soon as a(4) > a(5), while A050282(4) = A050282(5) = a(5). - M. F. Hasler, Apr 13 2019
a(12) > 99*10^9. - Giovanni Resta, Oct 02 2019
a(13) > 22*10^12. - Dmitry Petukhov, Jan 26 2020
a(14) > 50*10^12. - Dmitry Petukhov, Oct 28 2021

Crossrefs

Cf. A050282 (same for at least three 3s); A050279, A035117, A096756, A096758, A096759, A096760, A096761, A096762, A096763 (analog for digits 0, 1, 2, 4, ...).

Extensions

a(11) from Giovanni Resta, Oct 02 2019
a(12) from Dmitry Petukhov, Jan 26 2020
a(13) from Dmitry Petukhov, Oct 28 2021

A068987 a(n) is the first position in the digit sequence 3,1,4,1,5,9,.... of Pi where the pattern "1,2,...,n" occurs (where position of the initial 3 is 1).

Original entry on oeis.org

2, 149, 1925, 13808, 49703, 2458886, 9470345, 186557267, 523551503, 191278379840, 4368196101672
Offset: 1

Views

Author

Joseph L. Pe, Apr 01 2002

Keywords

Comments

1. We may never know if a(n) is defined for all n.
2. We split up the digits of any number > 9 in the pattern, e.g., if n = 11, we search for the pattern "1,2,3,4,5,6,7,8,9,1,0,1,1".
3. The pattern "1,2,3,4,5,6" does not occur before the 100,000th term in the digit sequence of Pi.
Two more terms a(6) and a(7) were found via the referenced Pi-Search link [Andersen], through which 100 million digits of Pi are currently available. - Rick L. Shepherd, Oct 10 2002
200 million digits now available at Pi-Search page. - Rick L. Shepherd, Aug 06 2006
This sequence uses position = 1 for the initial digit 3 of Pi, while A121280(n) = a(n)-1 starts counting at 0, as does the "Pi search page" and sequences A035117, A050279 - A050287, A048940, A096755 - A096763. - M. F. Hasler, Mar 18 2017
a(10) > 2*10^9. - M. F. Hasler, Apr 13 2019
a(12) > 22*10^12. - Dmitry Petukhov, Jan 29 2020

References

  • Wacław Sierpiński, O stu prostych, ale trudnych zagadnieniach arytmetyki. Warsaw: PZWS, 1959, p. 32.

Crossrefs

First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
First occurrence of n: A176341; of concatenate(1,...,n): A121280 = A068987 - 1.
Cf. A000796: Decimal expansion (or digits) of Pi.

Programs

  • Mathematica
    p = ToString[N[Pi, 50000]/10]; t = {1, 12, 123, 1234, 12345}; g[n_] := StringPosition[p, ToString[n]][[1]][[1]] - 2; Table[g[t[[i]]], {i, 1, 5}]

Formula

a(n) = A121280(n) + 1. - M. F. Hasler, Apr 13 2019

Extensions

More terms from Rick L. Shepherd, Oct 10 2002
a(8) from Rick L. Shepherd, Aug 06 2006
Additional term a(9), using subidiom search engine, from M. F. Hasler, Apr 13 2019
a(10)-a(11) from Dmitry Petukhov, Jan 16 2020

A121280 Position where concatenate(1,...,n) occurs for the first time in the decimals of Pi (where 3, 1, 4,... are at position 0, 1, 2,...).

Original entry on oeis.org

1, 148, 1924, 13807, 49702, 2458885, 9470344, 186557266, 523551502, 191278379839, 4368196101671
Offset: 1

Views

Author

Keywords

Comments

This sequence uses the same convention for the "position" as sequences A035117, A050279 - A050287, A048940, A096755 - A096763, while A068987(n) = a(n)+1 counts the positions of 3,1,4,.... as 1,2,3,... - M. F. Hasler, Mar 18 2017
a(10) > 2*10^9. - M. F. Hasler, Apr 13 2019
a(12) > 22*10^12. - Dmitry Petukhov, Jan 29 2020

Crossrefs

First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
Cf. A176341: first occurrence of n; A121280 = A068987 - 1: first occurrence of concatenate(1,...,n).
Cf. A000796: Decimal expansion (or digits) of Pi.

Formula

a(n) = A068987(n) - 1.

Extensions

New definition and cross-references from M. F. Hasler, Mar 18 2017
Additional term a(9), using subidiom search engine, from M. F. Hasler, Apr 13 2019
a(10)-a(11) from Dmitry Petukhov, Jan 16 2020
Showing 1-10 of 13 results. Next