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 1-2 of 2 results.

A359621 Number of edge cuts in the n-prism graph.

Original entry on oeis.org

1, 4, 31, 314, 3013, 27060, 232671, 1947118, 16021801, 130447976, 1055068595, 8498016994, 68269451069, 547562782044, 4387403278023, 35132904838614, 281226897433681, 2250607478637648, 18008682685966299, 144087851840540874, 1152791046751807845
Offset: 0

Views

Author

Eric W. Weisstein, Jan 07 2023

Keywords

Comments

The n-prism graph is defined from n >= 3. The sequence has been extrapolated to n = 0 using the recurrence. - Andrew Howroyd, Jan 26 2023

Crossrefs

Cf. A359620.

Programs

  • Mathematica
    Table[2 + 8^n + n + (((17^(-1/2) - 1) n - 2) (5 + Sqrt[17])^n - ((17^(-1/2) + 1) n + 2) (5 - Sqrt[17])^n)/2^(n + 1), {n, 0, 20}] // Expand (* Eric W. Weisstein, Dec 01 2024 *)
    LinearRecurrence[{20, -146, 488, -777, 612, -228, 32}, {1, 4, 31, 314, 3013, 27060, 232671}, 20] (* Eric W. Weisstein, Dec 01 2024 *)
    CoefficientList[Series[-(1 - 16 x + 97 x^2 - 210 x^3 + 84 x^4 + 12 x^5 + 4 x^6)/((-1 + x)^2 (-1 + 8 x) (1 - 5 x + 2 x^2)^2), {x, 0, 20}], x]
  • PARI
    Vec((1 - 16*x + 97*x^2 - 210*x^3 + 84*x^4 + 12*x^5 + 4*x^6)/((1 - x)^2*(1 - 8*x)*(1 - 5*x + 2*x^2)^2) + O(x^21)) \\ Andrew Howroyd, Jan 26 2023

Formula

G.f.: (1 - 16*x + 97*x^2 - 210*x^3 + 84*x^4 + 12*x^5 + 4*x^6)/((1 - x)^2*(1 - 8*x)*(1 - 5*x + 2*x^2)^2). - Andrew Howroyd, Jan 26 2023
a(n) = 20*a(n-1)-146*a(n-2)+488*a(n-3)-777*a(n-4)+612*a(n-5)-228*a(n-6)+32*a(n-7). - Eric W. Weisstein, Dec 01 2024

Extensions

a(0)-a(2) prepended and terms a(8) and beyond from Andrew Howroyd, Jan 26 2023

A378922 Number of minimal edge cuts in the n-antiprism graph.

Original entry on oeis.org

1, 1, 7, 28, 81, 191, 391, 722, 1233, 1981, 3031, 4456, 6337, 8763, 11831, 15646, 20321, 25977, 32743, 40756, 50161, 61111, 73767, 88298, 104881, 123701, 144951, 168832, 195553, 225331, 258391, 294966, 335297, 379633, 428231, 481356, 539281, 602287, 670663, 744706, 824721
Offset: 0

Views

Author

Eric W. Weisstein, Dec 11 2024

Keywords

Comments

The n-antiprism graph is defined for n >= 3. The sequence has been extended to n = 0 using the formula. - Andrew Howroyd, Jun 09 2025

Crossrefs

Cf. A359620.

Programs

  • PARI
    a(n) = (2*n^4 - 3*n^3 + 13*n^2 - 12*n + 6)/6 \\ Andrew Howroyd, Jun 09 2025

Formula

From Andrew Howroyd, Jun 09 2025: (Start)
a(n) = 1 + 2*n*(n-1) + n^2*(n-1)*(2*n-1)/6.
a(n) = (2*n^4 - 3*n^3 + 13*n^2 - 12*n + 6)/6. (End)
From Elmo R. Oliveira, Sep 03 2025: (Start)
G.f.: (1 - 4*x + 12*x^2 - 7*x^3 + 6*x^4)/(1-x)^5.
E.g.f.: (6 + 18*x^2 + 9*x^3 + 2*x^4)*exp(x)/6.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5). (End)

Extensions

a(0)-a(2) prepended and a(7) onwards from Andrew Howroyd, Jun 09 2025
Showing 1-2 of 2 results.