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.

A065177 Table M(n,b) (columns: n >= 1, rows: b >= 0) gives the number of site swap juggling patterns with exact period n, using exactly b balls, where cyclic shifts are not counted as distinct.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 3, 6, 3, 1, 0, 6, 15, 12, 4, 1, 0, 9, 42, 42, 20, 5, 1, 0, 18, 107, 156, 90, 30, 6, 1, 0, 30, 294, 554, 420, 165, 42, 7, 1, 0, 56, 780, 2028, 1910, 930, 273, 56, 8, 1, 0, 99, 2128, 7350, 8820, 5155, 1806, 420, 72, 9, 1, 0, 186, 5781, 26936
Offset: 0

Views

Author

Antti Karttunen, Oct 19 2001

Keywords

Examples

			Upper left corner starts as:
  1, 0,  0,   0,    0,     0,     0, ...
  1, 1,  2,   3,    6,     9,    18, ...
  1, 2,  6,  15,   42,   107,   294, ...
  1, 3, 12,  42,  156,   554,  2028, ...
  1, 4, 20,  90,  420,  1910,  8820, ...
  1, 5, 30, 165,  930,  5155, 28830, ...
  1, 6, 42, 273, 1806, 11809, 77658, ...
  ...
		

Crossrefs

Row 1: A059966, row 2: A065178, row 3: A065179, row 4: A065180.
Column 1: A002378, column 2: A059270.
Main diagonal gives A306173.
Cf. also A065167. trinv given at A054425.

Programs

  • Maple
    [seq(DistSS_table(j),j=0..119)]; DistSS_table := (n) -> DistSS((((trinv(n)-1)*(((1/2)*trinv(n))+1))-n)+1, (n-((trinv(n)*(trinv(n)-1))/2)));
    with(numtheory); DistSS := proc(n,b) local d,s; s := 0; for d in divisors(n) do s := s+mobius(n/d)*((b+1)^d - b^d); od; RETURN(s/n); end;
  • Mathematica
    trinv[n_] := Floor[(1 + Sqrt[8 n + 1])/2];
    DistSS[n_, b_] := DivisorSum[n, MoebiusMu[n/#]*((b + 1)^# - b^#)&] /n;
    a[n_] := DistSS[(((trinv[n] - 1)*(((1/2)*trinv[n]) + 1)) - n) + 1, (n - ((trinv[n]*(trinv[n] - 1))/2))];
    Table[a[n], {n, 0, 119}] (* Jean-François Alcover, Mar 06 2016, adapted from Maple *)

Formula

Row n is the inverse Euler transform of j-> n^(j-1). - Alois P. Heinz, Jun 23 2018

A075147 Number of Lyndon words (aperiodic necklaces) with n beads of n colors.

Original entry on oeis.org

1, 1, 8, 60, 624, 7735, 117648, 2096640, 43046640, 999989991, 25937424600, 743008120140, 23298085122480, 793714765724595, 29192926025339776, 1152921504338411520, 48661191875666868480, 2185911559727674682148, 104127350297911241532840, 5242879999999487999992020
Offset: 1

Views

Author

Christian G. Bower, Sep 04 2002

Keywords

Crossrefs

Main diagonal of A074650 and A143325.

Programs

  • Maple
    with(numtheory):
    a:= n-> add(n^d *mobius(n/d), d=divisors(n))/n:
    seq(a(n), n=1..25);  # Alois P. Heinz, Dec 21 2014
  • Mathematica
    Table[Total@Map[ MoebiusMu[#1] n^(n/#1 - 1) &, Divisors[n]], {n, 20}] (* Olivier Gérard, Aug 05 2016 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(n/d) * n^d) / n; \\ Amiram Eldar, May 29 2025

Formula

a(n) = (1/n) * Sum_{d|n} mu(n/d)*n^d.
Asymptotic to n^(n-1) = A000169(n).
a(n) is the n-th term of the inverse Euler transform of j-> n^j. - Alois P. Heinz, Jun 23 2018
a(n) = [x^n] Sum_{k>=1} mu(k)*log(1/(1 - n*x^k))/k. - Ilya Gutkovskiy, May 20 2019

A316073 a(n) is the n-th term of the inverse Weigh transform of j-> n^(j-1).

Original entry on oeis.org

1, 2, 6, 46, 420, 5185, 77658, 1376768, 28133616, 651325653, 16846515510, 481472773386, 15067838554860, 512473605894549, 18821719654854998, 742395982483047976, 31299550394528466960, 1404629090183809673484, 66851805805525048040334, 3363381327122907537090234
Offset: 1

Views

Author

Alois P. Heinz, Jun 23 2018

Keywords

Crossrefs

Cf. A306173.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(binomial(g(i, k), j)*b(n-i*j, i-1,k), j=0..n/i)))
        end:
    g:= proc(n, k) option remember; k^(n-1)-b(n, n-1, k) end:
    a:= n-> g(n$2):
    seq(a(n), n=1..21);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0,
        Sum[Binomial[g[i, k], j] b[n - i j, i - 1, k], {j, 0, n/i}]]];
    g[n_, k_] := g[n, k] = k^(n - 1) - b[n, n - 1, k];
    a[n_] := g[n, n];
    Array[a, 21] (* Jean-François Alcover, Dec 29 2020, after Alois P. Heinz *)

Formula

a(n) ~ (1 - exp(-1)) * n^(n-1). - Vaclav Kotesovec, Oct 08 2019

A383042 Square array A(n,k), n >= 1, k >= 1, read by antidiagonals downwards, where A(n,k) is the n-th term of the inverse Euler transform of j-> k^(j-1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 6, 3, 0, 1, 4, 12, 15, 6, 0, 1, 5, 20, 42, 42, 9, 0, 1, 6, 30, 90, 156, 107, 18, 0, 1, 7, 42, 165, 420, 554, 294, 30, 0, 1, 8, 56, 273, 930, 1910, 2028, 780, 56, 0, 1, 9, 72, 420, 1806, 5155, 8820, 7350, 2128, 99, 0
Offset: 1

Views

Author

Seiichi Manyama, Apr 13 2025

Keywords

Examples

			Square array begins:
  1,  1,   1,    1,    1,     1,     1, ...
  0,  1,   2,    3,    4,     5,     6, ...
  0,  2,   6,   12,   20,    30,    42, ...
  0,  3,  15,   42,   90,   165,   273, ...
  0,  6,  42,  156,  420,   930,  1806, ...
  0,  9, 107,  554, 1910,  5155, 11809, ...
  0, 18, 294, 2028, 8820, 28830, 77658, ...
  ...
		

Crossrefs

Columns k=1..5 give A000007, A059966, A065178, A065179, A065180.
Main diagonal gives A306173.
Cf. A065177 (another version).

Programs

  • PARI
    a(n, k) = sumdiv(n, d, moebius(n/d)*(k^d-(k-1)^d))/n;

Formula

A(n,k) = (1/n) * Sum_{d|n} mu(n/d) * (k^d - (k-1)^d).
A(n,k) = (1/n) * (k^n - (k-1)^n - Sum_{d
A(n,k) = A074650(n,k) - A074650(n,k-1).
Product_{n>=1} 1/(1 - x^n)^A(n,k) = (1 - (k-1)*x)/(1 - k*x).
G.f. of column k: Sum_{j>=1} mu(j) * log(1 + x^j/(1 - k*x^j)) / j.
Showing 1-4 of 4 results.