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 1-3 of 3 results.

A364668 Domination and lower independence number of the n-Goldberg graph.

Original entry on oeis.org

0, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 25, 27, 29, 31, 33, 36, 38, 40, 42, 44, 47, 49, 51, 53, 55, 58, 60, 62, 64, 66, 69, 71, 73, 75, 77, 80, 82, 84, 86, 88, 91, 93, 95, 97, 99, 102, 104, 106, 108, 110, 113, 115, 117, 119, 121, 124, 126, 128, 130, 132
Offset: 0

Views

Author

Eric W. Weisstein, Aug 01 2023

Keywords

Comments

The Goldberg graph is defined for n >= 3.
Extended to n = 0 through 2 using the formula/recurrence.
Disagrees with A195167(n) at n = 26, 31, 36, 41, ....

Crossrefs

Cf. A382431.

Programs

  • Mathematica
    Table[(11 n - Cos[2 n Pi/5] - Cos[4 n Pi/5] + Sqrt[1 + 2/Sqrt[5]] Sin[2 n Pi/5] + Sqrt[1 - 2/Sqrt[5]] Sin[4 n Pi/5] + 2)/5, {n, 0, 20}]
    LinearRecurrence[{1, 0, 0, 0, 1, -1}, {0, 3, 5, 7, 9, 11}, 20]
    CoefficientList[Series[x (3 + 2 x + 2 x^2 + 2 x^3 + 2 x^4)/((-1 + x)^2 (1 + x + x^2 + x^3 + x^4)), {x, 0, 20}], x]

Formula

a(n) = a(n-1) + a(n-5) - a(n-6).
G.f.: x*(3+2*x+2*x^2+2*x^3+2*x^4)/((-1+x)^2*(1+x+x^2+x^3+x^4)).
a(n) = floor((11*n + 4)/5). - Andrew Howroyd, May 25 2025

Extensions

Name extended by Eric W. Weisstein, Mar 10 2025

A382384 Number of minimum connected dominating sets in the n-Goldberg graph.

Original entry on oeis.org

6, 96, 290, 744, 1974, 5376, 15642, 45480, 124014, 343008, 944658, 2596776, 7116390, 19409664, 52694730, 142812648, 385840030, 1039911520, 2796034626, 7501233256, 20084164374, 53677896192, 143214557050, 381504047912, 1014784646094, 2695617288672, 7151420301682
Offset: 3

Views

Author

Eric W. Weisstein, Mar 23 2025

Keywords

Comments

The connected domination number is given by 4*n - 1 = A004767(n - 1). - Andrew Howroyd, May 25 2025

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{4, 2, -16, -7, 20, 24, -64, 97, 236, -246, -368, 7, 252, -772, -64, 1920, 0, -1024}, {6, 96, 290, 744, 1974, 5376, 15642, 45480, 124014, 343008, 944658, 2596776, 7116390, 19409664, 52694730, 142812648, 385840030, 1039911520}, 20] (* Eric W. Weisstein, Jun 04 2025 *)
    CoefficientList[Series[2 (3 + 36 x - 53 x^2 - 256 x^3 - 2 x^4 + 592 x^5 + 1030 x^6 + 616 x^7 - 2817 x^8 - 2804 x^9 + 2591 x^10 + 2200 x^11 - 2592 x^12 - 2176 x^13 + 5168 x^14 + 3840 x^15 - 2304 x^16 - 2048 x^17)/((1 - x)^2 (1 + x)^2 (1 - x - 4 x^2)^2 (1 - x + 2 x^2)^2 (1 - x^2 - 4 x^3)^2), {x, 0, 20}], x] (* Eric W. Weisstein, Jun 04 2025 *)

Formula

G.f.: 2*x^3*(3 + 36*x - 53*x^2 - 256*x^3 - 2*x^4 + 592*x^5 + 1030*x^6 + 616*x^7 - 2817*x^8 - 2804*x^9 + 2591*x^10 + 2200*x^11 - 2592*x^12 - 2176*x^13 + 5168*x^14 + 3840*x^15 - 2304*x^16 - 2048*x^17)/((1 - x)*(1 + x)*(1 - x + 2*x^2)*(1 - x - 4*x^2)*(1 - x^2 - 4*x^3))^2. - Andrew Howroyd, May 25 2025

Extensions

a(7) onwards from Andrew Howroyd, May 24 2025

A382657 Number of minimum total dominating sets in the n-Goldberg graph.

Original entry on oeis.org

16, 277, 10, 2386, 28, 33301, 360, 10, 4334, 60, 67288, 728, 10, 9856, 102, 150750, 1292, 10, 19222, 154, 299368, 2124, 10, 34112, 216, 549276, 3306, 10, 56730, 288, 951456, 4930, 10, 89916, 370, 1576202, 7098, 10, 137268, 462, 2518596, 9922, 10, 203274, 564, 3905148, 13524, 10
Offset: 3

Views

Author

Eric W. Weisstein, Apr 02 2025

Keywords

Comments

For n > 3, the total domination number is given by 2*floor((7*n+4)/5) = 2*A047332(n+1). For n = 3, the total domination number is 9. - Andrew Howroyd, May 24 2025

Crossrefs

Cf. A382431.

Programs

  • PARI
    a(n) = { my(m=n\5+1,r=-n%5); if(n<=8, [16, 277, 10, 2386, 28, 33301][n-2], if(r<=2, if(r==0, 10, n*if(r==1, (m + 13)*(m^2 + 2*m + 24)/12, (m^7 + 70*m^6 + 1750*m^5 + 39340*m^4 + 525889*m^3 + 2944270*m^2 + 15922920*m + 12216960)/20160)), n*if(r==3, (m + 2), (m^5 + 35*m^4 + 365*m^3 + 5485*m^2 + 21114*m + 16200)/360) )) } \\ Andrew Howroyd, May 24 2025

Formula

a(5*n) = 10.
From Andrew Howroyd, May 24 2025: (Start)
a(5*n-1) = (5*n-1)*(n + 13)*(n^2 + 2*n + 24)/12 for n >= 2;
a(5*n-2) = (5*n-2)*(n^7 + 70*n^6 + 1750*n^5 + 39340*n^4 + 525889*n^3 + 2944270*n^2 + 15922920*n + 12216960)/20160 for n >= 3;
a(5*n-3) = (5*n-3)*(n + 2) for n >= 2;
a(5*n-4) = (5*n-4)*(n^5 + 35*n^4 + 365*n^3 + 5485*n^2 + 21114*n + 16200)/360 for n >= 3. (End)

Extensions

a(8)-a(12) from Eric W. Weisstein, May 11 2025
a(13) onwards from Andrew Howroyd, May 24 2025
Showing 1-3 of 3 results.