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 1-5 of 5 results.

A289170 Number of dominating sets in the n X n white bishop graph.

Original entry on oeis.org

3, 11, 201, 3413, 233727, 15544607, 4103802933, 1069035156713, 1107896230202475, 1142044772648964275, 4697484584102406799521, 19284763179499969013836925, 316392839278535985537956881623, 5187559573137612606140331666573383
Offset: 2

Views

Author

Eric W. Weisstein, Jun 26 2017

Keywords

Crossrefs

Programs

  • PARI
    Collect(sig,v,r,x)={forstep(r=r, 1, -1, my(w=sig[r]+1); v=vector(#v, k, sum(j=1, k, binomial(#v-j,k-j)*v[j]*x^(k-j)*(1+x)^(w-#v+j-1))-v[k])); v[#v]}
    DomSetCount(sig,x)={my(v=[1]); my(total=Collect(sig,v,#sig,x)); forstep(r=#sig, 1, -1, my(w=sig[r]+1); total+=Collect(sig, vector(w,k,if(k<=#v,v[k])), r-1, x); v=vector(w, k, sum(j=1, min(k,#v), binomial(w-j, k-j)*v[j]*x^(k-j)*(1+x)^(j-1)))); total}
    Bishop(n, white)=vector(n-if(white, n%2, 1-n%2), i, n-i+if(white, 1-i%2, i%2));
    a(n)=DomSetCount(Bishop(n,1),1); \\ Andrew Howroyd, Nov 05 2017

Extensions

Terms a(8) and beyond from Andrew Howroyd, Nov 05 2017

A287897 Number of minimal dominating sets in the n X n white bishop graph.

Original entry on oeis.org

2, 6, 19, 78, 425, 2484, 18167, 137444, 1238979
Offset: 2

Views

Author

Eric W. Weisstein, Aug 02 2017

Keywords

Crossrefs

Extensions

a(7)-a(10) from Andrew Howroyd, Nov 30 2017

A289145 Number of connected dominating sets in the n X n black bishop graph.

Original entry on oeis.org

1, 3, 16, 128, 4528, 176192, 25823200, 3695526272
Offset: 1

Views

Author

Eric W. Weisstein, Jun 26 2017

Keywords

Crossrefs

Extensions

a(8) from Andrew Howroyd, Sep 04 2017

A290769 Number of (non-null) connected induced subgraphs in the n X n white bishop graph.

Original entry on oeis.org

3, 13, 168, 2844, 194751, 14062789, 3852814320, 1039212524160
Offset: 2

Views

Author

Eric W. Weisstein, Aug 10 2017

Keywords

Crossrefs

Extensions

a(8)-a(9) from Andrew Howroyd, Aug 15 2017

A381727 Number of minimum connected dominating sets in the n X n white bishop graph.

Original entry on oeis.org

2, 4, 1, 4, 13, 64, 513, 4480, 41197, 444416, 5597201, 77253632, 1153902701, 18870222848, 336018968449, 6428081455104, 131386321421901, 2865273888571392, 66426533670738769, 1629643279560867840, 42175861619149917325, 1148845693539400548352, 32856688248674995989889
Offset: 2

Views

Author

Eric W. Weisstein, Mar 05 2025

Keywords

Crossrefs

Cf. A381726 (black bishop).

Programs

  • Mathematica
    Join[{2, 4}, Table[Sum[(2 k)^(n - 2 k - 2) (n - 2 k - 1)^(2 k - 1), {k, Floor[n/2] - 1}], {n, 4, 20}]] (* Eric W. Weisstein, Mar 22 2025 *)
  • PARI
    \\ B(n, k) is A072590.
    B(n,k) = n^(k-1) * k^(n-1)
    a(n) = if(n <= 3, 2*n-2, sum(k=1, n\2-1, B(n-1-2*k, 2*k))) \\ Andrew Howroyd, Mar 20 2025

Formula

a(n) = Sum_{k=1..floor(n\2)-1} A072590(n-1-2*k, 2*k) for n >= 4. - Andrew Howroyd, Mar 20 2025

Extensions

a(10) onwards from Andrew Howroyd, Mar 20 2025
Showing 1-5 of 5 results.