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.

A191250 Fixed point of the morphism 0 -> 01, 1 -> 02, 2 -> 001.

Original entry on oeis.org

0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 1, 0
Offset: 1

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Author

Clark Kimberling, May 28 2011

Keywords

Comments

A few 3-substitution sequences:
A191250: 0 -> 01, 1 -> 02, 2 -> 001
A191254: 0 -> 01, 1 -> 02, 2 -> 01
A191255: 0 -> 01, 1 -> 02, 2 -> 03, 3 -> 01
A191258: 0 -> 01, 1 -> 02, 2 -> 03, 3 -> 001
A191261: 0 -> 01, 1 -> 002, 2 -> 01
A191265: 0 -> 001, 1 -> 002, 2 -> 01
A191269: 0 -> 001, 1 -> 02, 2 -> 01
See also A189576 and A189628.

Crossrefs

Programs

  • Mathematica
    t = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0, 2}, 2 -> {0, 0, 1}}] &, {0},8]  (* A191250 *)
    Flatten[Position[t, 0]]  (* A191251 *)
    Flatten[Position[t, 1]]  (* A191252 *)
    Flatten[Position[t, 2]]  (* A191253 *)

A043306 Sum of all digits in all base-b representations for n, for 2 <= b <= n.

Original entry on oeis.org

1, 3, 4, 8, 10, 16, 17, 21, 25, 35, 34, 46, 52, 60, 58, 74, 73, 91, 92, 104, 114, 136, 128, 144, 156, 168, 171, 199, 193, 223, 221, 241, 257, 281, 261, 297, 315, 339, 333, 373, 367, 409, 416, 430, 452, 498, 472, 508, 515, 547, 556, 608, 598, 638, 634, 670, 698, 756, 717, 777
Offset: 2

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Author

Keywords

Examples

			5 = 101_2 = 12_3 = 11_4 = 10_5. Thus a(5) = 2 + 3 + 2 + 1 = 8.
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[Total[First[RealDigits[n, i]]], {i, 2, n}], {n, 2, 80}] (* Carl Najafi, Aug 16 2011 *)
  • PARI
    a(n) = sum(i=2, n, vecsum(digits(n, i))); \\ Michel Marcus, Jan 03 2017
    
  • PARI
    a(n) = sum(b=2, n, sumdigits(n, b)); \\ Michel Marcus, Aug 18 2017
    
  • Python
    from sympy.ntheory.digits import digits
    def a(n): return sum(sum(digits(n, b)[1:]) for b in range(2, n+1))
    print([a(n) for n in range(2, 62)]) # Michael S. Branicky, Apr 04 2022

Formula

From Vladimir Shevelev, Jun 03 2011: (Start)
a(n) = (n-1)*n - Sum_{i=2..n} (i-1)*Sum_{r>=1} floor(n/i^r).
a(n) <= (n-1)^2*log(n+1)/log(n).
Problem: find a better upper estimate. (End)
From Amiram Eldar, Apr 16 2021: (Start)
a(n) = A014837(n) + 1.
a(n) ~ (1-Pi^2/12)*n^2 + O(n^(3/2)) (Fissum, 2020). (End)
Showing 1-2 of 2 results.