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.

A157686 a(n) = A157684(n) - A157685(n).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Mar 04 2009

Keywords

Comments

For n>=1 a(n) = A000002(n+1)-1 and also a(n) = A123594(n+3).

Crossrefs

Partial sums of A054354.

A157685 a(n)=#{1<=k<=n : [K(k),K(k+1)]=[2,1]} where K=A000002.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 26, 26, 26
Offset: 1

Views

Author

Benoit Cloitre, Mar 04 2009

Keywords

Comments

Presumably a(n)=n/3+o(n)

Crossrefs

Programs

Formula

a(n)=sum(k=1,n,(1-K(k))*(K(k+1)-K(k))) where K(k)=A000002(k).

A157687 a(n) = n - A054353(A156351(n)).

Original entry on oeis.org

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

Views

Author

Benoit Cloitre, Mar 04 2009

Keywords

Crossrefs

Formula

a(n) = 1 iff n is in A078649, a(n) = 0 iff n is in A054353.
a(n) = n-A054353(A157684(n)+A157685(n)).
a(n) = 1 - A156728(n). - Alan Michael Gómez Calderón, Dec 19 2024

A157654 Triangle T(n, k, m) = 1 if k = 0 or k = n, otherwise m*abs( (n-k)^(m-1) - k^(m-1) ), with m = 2, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, 2, 2, 1, 1, 4, 0, 4, 1, 1, 6, 2, 2, 6, 1, 1, 8, 4, 0, 4, 8, 1, 1, 10, 6, 2, 2, 6, 10, 1, 1, 12, 8, 4, 0, 4, 8, 12, 1, 1, 14, 10, 6, 2, 2, 6, 10, 14, 1, 1, 16, 12, 8, 4, 0, 4, 8, 12, 16, 1
Offset: 0

Views

Author

Roger L. Bagula, Mar 03 2009

Keywords

Comments

For the cases of m = 0, 1 the triangles reduce to T(n, k, m) = A103451(n, k). - G. C. Greubel, Dec 13 2021

Examples

			Triangle begins as:
  1;
  1,  1;
  1,  0,  1;
  1,  2,  2,  1;
  1,  4,  0,  4,  1;
  1,  6,  2,  2,  6,  1;
  1,  8,  4,  0,  4,  8,  1;
  1, 10,  6,  2,  2,  6, 10,  1;
  1, 12,  8,  4,  0,  4,  8, 12,  1;
  1, 14, 10,  6,  2,  2,  6, 10, 14,  1;
  1, 16, 12,  8,  4,  0,  4,  8, 12, 16, 1;
		

Crossrefs

Programs

  • Magma
    T:= func< n,k,q | k eq 0 or k eq n select 1 else q*Abs( (n-k)^(q-1) - k^(q-1) ) >;
    [T(n,k,2): k in [0..n], n in [0..15]]; // G. C. Greubel, Dec 13 2021
    
  • Mathematica
    T[n_, k_, m_]:= T[n, k, m]= If[k==0 || k==n, 1, m*Abs[(n-k)^(m-1) - k^(m-1)]];
    Table[T[n,k,2], {n,0,15}, {k,0,n}]//Flatten
  • Sage
    def A157684(n,k,q): return 1 if (k==0 or k==n) else q*abs((n-k)^(q-1) - k^(q-1))
    flatten([[A157684(n,k,2) for k in (0..n)] for n in (0..15)]) # G. C. Greubel, Dec 13 2021

Formula

T(n, k, m) = 1 if k = 0 or k = n, otherwise m*abs( (n-k)^(m-1) - k^(m-1) ), with m = 2.
From G. C. Greubel, Dec 13 2021: (Start)
Sum_{k=0..n} T(n, k, 2) = (-1)*[n==0] + A244800(n-1).
T(2*n, n, 2) = A000007(n). (End)

Extensions

Edited by G. C. Greubel, Dec 13 2021
Showing 1-4 of 4 results.