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 1-4 of 4 results.

A224365 a(n) = A063674(n+1) - A063674(n).

Original entry on oeis.org

10, 3, 3, 3, 157, 22, 22, 22, 22, 22, 22, 22, 22, 51808, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355, 355
Offset: 1

Views

Author

Paul Curtz, Apr 09 2013

Keywords

Comments

The repeated terms (3, 22, 355, 5419351, ... from A063674) are the numerators of fractions (3/1, 22/7, 355/113, 5419351/1725033, ...) leading to Pi.
Zu Chongzhi (5th century) discovered 22/7 and 355/113. Adriaan Anthonisz Metius rediscovered 355/113 in 1585.
First differences of A063673 give the denominators: 3, 1, 1, 1, 50, 7, 7, 7, 7, 7, 7, 7, 7, 16489, 113, 113, ... .
Hence 10/3, 157/50, 51808/16489, ... .

Crossrefs

Programs

  • Mathematica
    A224365 = Reap[ For[ delta0 = 1; d = 1, d < 10^5, d++, delta = Abs[Pi - Round[Pi*d]/d]; If[ delta < delta0, Sow[ Round[Pi*d]]; delta0 = delta]]][[2, 1]] // Differences (* Jean-François Alcover, Apr 10 2013 *)

Formula

a(n) = A063674(n+1) - A063674(n).

A226042 Decimal expansion of Pi-333/106.

Original entry on oeis.org

0, 0, 0, 0, 8, 3, 2, 1, 9, 6, 2, 7, 5, 2, 9, 0, 8, 7, 5, 1, 9, 2, 4, 7, 1, 5, 6, 8, 6, 4, 4, 0, 8, 5, 4, 4, 5, 7, 4, 5, 2, 7, 8, 8, 9, 9, 4, 1, 1, 4, 3, 5, 5, 6, 8, 2, 4, 0, 0, 1, 1, 9, 6, 0, 8, 1, 4, 0, 1, 3, 1, 1, 9, 4, 6, 5, 8, 6, 3, 5, 7, 1, 1, 8, 6, 0, 0, 8, 6, 3, 0, 7, 7, 9, 6, 6, 1, 2, 4, 5
Offset: 0

Views

Author

Jean-François Alcover, May 24 2013

Keywords

Examples

			0.000083219627529087519247156864408544574527889941143556824001196081401311946...
		

Crossrefs

Programs

Formula

Pi-333/106 = 1/530*integral_{x=0..1} x^5*(1-x)^6*(197+462*x^2)/(1+x^2).

A159878 The digits of Pi whose spellings in English contain no i's.

Original entry on oeis.org

3, 1, 4, 1, 2, 3, 7, 3, 2, 3, 4, 2, 4, 3, 3, 3, 2, 7, 0, 2, 4, 1, 7, 1, 3, 3, 7, 1, 0, 2, 0, 7, 4, 4, 4, 2, 3, 0, 7, 1, 4, 0, 2, 2, 0, 2, 0, 3, 4, 2, 3, 4, 2, 1, 1, 7, 0, 7, 2, 1, 4, 0, 1, 3, 2, 2, 3, 0, 4, 7, 0, 3, 4, 4, 0, 0, 2, 2, 3, 1, 7, 2, 3, 4, 0, 1, 2, 4, 1, 1, 1, 7, 4, 0, 2, 4, 1, 0, 2, 7, 0, 1, 3, 2, 1
Offset: 1

Views

Author

Cino Hilliard, Apr 25 2009

Keywords

Comments

Blind Pi: The series of digits of Pi A000796 after removal of any 5, 6, 8 or 9 (see A095763, A089589).
The difference of the value of this constant to Pi is 0.000355..., compared to a difference of 0.0012... = A003077 for 22/7.
The only other alpha language that has no numbers 0 to 9 with an i is Albanian.
It is natural to ask "is the constant defined in this way irrational, transcendental?"

Examples

			Pi = 3.1415... . The digit 5 or five contains an i in the spelling. So 5 is not in the sequence.
		

Programs

  • Mathematica
    Flatten[ RealDigits[Pi, 10, 174][[1]] /. {5 -> {}, 6 -> {}, 8 -> {}, 9 -> {}}] (* Robert G. Wilson v, May 27 2009 *)
  • PARI
    blindpi(n) =
    {
    default(realprecision,1000);
    local(pi,x);
    pi=Vec(Str(Pi*10^99));
    default(realprecision,28);
    for(x=1,n,
    if(pi[x]=="0"||pi[x]=="1"||pi[x]=="2"||pi[x]=="3"||pi[x]=="4"||pi[x]=="7",
    print1(pi[x]",");
    );
    );
    }

Extensions

Edited by R. J. Mathar, Apr 28 2009

A226043 Decimal expansion of 355/113-Pi.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 2, 6, 6, 7, 6, 4, 1, 8, 9, 0, 6, 2, 4, 2, 2, 3, 1, 2, 3, 6, 8, 9, 3, 2, 8, 8, 6, 4, 9, 6, 3, 3, 3, 8, 0, 4, 0, 5, 1, 9, 5, 2, 3, 2, 7, 8, 0, 7, 3, 4, 3, 6, 3, 9, 4, 7, 8, 4, 8, 8, 6, 4, 3, 7, 7, 0, 7, 0, 4, 9, 4, 1, 4, 4, 3, 8, 4, 9, 8, 4, 1, 2, 8, 0, 8, 5, 2, 5, 7, 3, 1, 9, 7, 5
Offset: 0

Views

Author

Jean-François Alcover, May 24 2013

Keywords

Examples

			0.000000266764189062422312368932886496333804051952327807343639478488643770704...
		

Crossrefs

Programs

  • Mathematica
    Join[{0, 0, 0, 0, 0, 0}, RealDigits[355/113 - Pi, 10, 94][[1]]]
  • PARI
    355/113-Pi \\ Charles R Greathouse IV, Oct 01 2022

Formula

355/113-Pi = 1/3164*integral_{x=0..1} x^8*(1-x)^8*(25+816*x^2)/(1+x^2).
Showing 1-4 of 4 results.