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.

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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 *)

A346122 n times the n-th digit of the decimal expansion of Pi.

Original entry on oeis.org

3, 2, 12, 4, 25, 54, 14, 48, 45, 30, 55, 96, 117, 98, 135, 48, 34, 54, 152, 80, 126, 44, 138, 96, 75, 78, 216, 84, 58, 210, 279, 160, 0, 68, 280, 288, 148, 38, 351, 280, 41, 252, 387, 132, 405, 414, 141, 336, 245, 50, 0, 260, 424, 108, 0, 504, 399, 232, 531
Offset: 1

Views

Author

Harvey P. Dale, Jul 05 2021

Keywords

Examples

			The first  digit of the decimal expansion of Pi is 3, so a(1) = 1*3 = 3.
The second digit of the decimal expansion of Pi is 1, so a(2) = 2*1 = 2.
The third  digit of the decimal expansion of Pi is 4, so a(3) = 3*4 = 12.
		

Crossrefs

Cf. A000796, A014976 (zeros), A053745 (fixed points).

Programs

  • Mathematica
    Module[{nn=120,pid},pid=RealDigits[Pi,10,nn][[1]];Table[n pid[[n]],{n,nn}]]
  • Python
    from sympy import S
    def aupton(terms):
        digits_of_pi = "0" + str(S.Pi.n(terms+1)).replace('.', '')
        return [n*int(digits_of_pi[n]) for n in range(1, terms+1)]
    print(aupton(59)) # Michael S. Branicky, Jul 08 2021
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