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.

A289164 Number of dominating sets in the n X n black bishop graph.

Original entry on oeis.org

1, 3, 25, 201, 6979, 233727, 31262125, 4103802933, 2141080094839, 1107896230202475, 2284899650399760961, 4697484584102406799521, 38572957675399837886746123, 316392839278535985537956881623, 10375350180532286630209934837828053
Offset: 1

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,0),1); \\ Andrew Howroyd, Nov 05 2017

Extensions

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

A286886 Number of minimal dominating sets in the n X n black bishop graph.

Original entry on oeis.org

1, 2, 5, 19, 84, 425, 2725, 18167, 147458, 1238979
Offset: 1

Views

Author

Eric W. Weisstein, Aug 02 2017

Keywords

Crossrefs

Extensions

a(7) from Eric W. Weisstein, Nov 29 2017
a(8)-a(10) from Andrew Howroyd, Nov 30 2017

A289169 Number of connected dominating sets in the n X n white bishop graph.

Original entry on oeis.org

3, 9, 128, 2394, 176192, 13140504, 3695526272
Offset: 2

Views

Author

Eric W. Weisstein, Jun 26 2017

Keywords

Crossrefs

Extensions

a(8) from Andrew Howroyd, Sep 04 2017

A290719 Number of (non-null) connected induced subgraphs in the n X n black bishop graph.

Original entry on oeis.org

1, 3, 22, 168, 5251, 194751, 27478594, 3852814320, 2065546517563
Offset: 1

Views

Author

Eric W. Weisstein, Aug 09 2017

Keywords

Crossrefs

Extensions

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

A381726 Number of minimum connected dominating sets in the n X n black bishop graph.

Original entry on oeis.org

1, 2, 1, 1, 2, 13, 83, 513, 4052, 41197, 462069, 5597201, 76094134, 1153902701, 18981358311, 336018968449, 6413439874792, 131386321421901, 2867812411156521, 66426533670738769, 1629082910078009770, 42175861619149917325, 1148999152027728530363, 32856688248674995989889
Offset: 1

Views

Author

Eric W. Weisstein, Mar 05 2025

Keywords

Crossrefs

Cf. A381727 (white bishop).

Programs

  • Mathematica
    Join[{1, 2}, Table[Sum[(2 k - 1)^(n - 2 k - 1) (n - 2 k)^(2 (k - 1)), {k, Floor[(n - 1)/2]}], {n, 3, 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 <= 2, n, sum(k=1, (n-1)\2, B(n-2*k, 2*k-1))) \\ Andrew Howroyd, Mar 20 2025

Formula

a(n) = Sum_{k=1..floor((n-1)/2)} A072590(n-2*k, 2*k-1) for n >= 3. - Andrew Howroyd, Mar 20 2025

Extensions

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