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 1-2 of 2 results.

A373079 Decimal digits of Pi selected by stepping forward d places at digit d or 10 places if d=0.

Original entry on oeis.org

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

Views

Author

Karl Levy, May 22 2024

Keywords

Comments

Are the digits uniformly distributed?

Examples

			The sequence starts with the first digit of the decimal expansion of Pi, which is 3. The next term is the digit 3 places after this, namely, 1, and so on.
The digits selected from Pi begin
  Pi = 3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, ...
       ^        ^  ^              ^        ^
		

Crossrefs

Programs

  • Mathematica
    a={3}; s=1; For[n=2, n<=100, n++, s+=Part[a,n-1]+10KroneckerDelta[Part[a,n-1]]; digits=First[RealDigits[Pi,10,s]]; AppendTo[a,Part[digits,s]]]; a (* Stefano Spezia, May 31 2024 *)

Formula

a(n) = the (1 + Sum_{i=1..n-1} a(i) + 10*delta(a(i),0))-th digit in the decimal expansion of Pi, where delta is the Kronecker symbol.

Extensions

a(25)-a(100) from Stefano Spezia, May 31 2024

A373307 Binary digits of Pi selected by stepping forward d+1 places at digit d, i.e., by skipping the next d places.

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0
Offset: 1

Views

Author

Karl Levy, May 31 2024

Keywords

Comments

Are the digits uniformly distributed? Are all digit sequences uniformly distributed?

Examples

			The sequence starts with the first digit of the binary expansion of Pi, which is 1. The next term is the digit 1+1 places after this, namely, 0, and so on.
The digits selected from Pi begin
  Pi=1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, ...
     ^     ^  ^  ^     ^  ^     ^  ^  ^  ^     ^
		

Crossrefs

Programs

  • Mathematica
    a={1}; s=1; For[n=2, n<=100, n++, s+=Part[a,n-1]+1; digits=First[RealDigits[Pi,2,s]]; AppendTo[a,Part[digits,s]]]; a

Formula

a(n) = the (n+a(1)+a(2)+...+a(n-1))-th digit in the binary expansion of Pi.
Showing 1-2 of 2 results.