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.

A143158 Triangle read by rows, T(n,k) = Sum_{j=k..n} mu(j).

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, Jul 27 2008

Keywords

Comments

Right border gives A008683.
Left border gives A002321.
Row sums give A068340.

Examples

			First few rows of the triangle =
   1;
   0, -1;
  -1, -2, -1;
  -1, -2, -1,  0;
  -2, -3, -2, -1, -1;
  -2, -3, -2, -1, -1, 0, -1;
  -2, -3, -2, -1, -1, 0, -1, 0;
  -1, -2, -1,  0,  0, 1,  0, 1, 1, 1;
  ...
For example, T(5,3) = (-2) = Sum(-1, 0, -1), since mu(n) = 1, -1, -1, 0, -1, ...
		

Crossrefs

Programs

  • Haskell
    import Data.List (tails)
    a143158 n k = a143158_tabl !! (n-1) !! (k-1)
    a143158_row n = a143158_tabl !! (n-1)
    a143158_tabl = map (map sum . init . tails) a054527_tabl
    -- Reinhard Zumkeller, Sep 04 2015
    
  • Mathematica
    Table[Sum[MoebiusMu@ j, {j, k, n}], {n, 14}, {k, n}] // Flatten (* Michael De Vlieger, Dec 17 2015 *)
  • PARI
    T(n,k) = sum(j=k,n,moebius(j))

Formula

Triangle read by rows, T(n,k) = Sum_{j=k..n} mu(j), where mu(n) = A008683.
T(n, k) = A000012(n) * (A008683(n) * 0^(n-k)) * A000012(n).

Extensions

47th term = T(10,2) corrected by Reinhard Zumkeller, Sep 04 2015