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.

A377771 Number of edge cuts in the n-trapezohedral graph.

Original entry on oeis.org

1, 13, 185, 3013, 51009, 864453, 14514449, 241137749, 3969473217, 64867543333, 1054153461745, 17059836799733, 275240835803937, 4430702562116805, 71206049773837905, 1142980976834497173, 18330756374528899457, 293794963549100393573, 4706588394482611291313, 75373885078381735479861
Offset: 0

Views

Author

Eric W. Weisstein, Nov 06 2024

Keywords

Comments

The sequence has been extended to n = 0 using the recurrence. - Andrew Howroyd, Dec 19 2024

Crossrefs

Cf. A356213.

Programs

  • Mathematica
    Table[16^n - 1 - 2^(n + 1) ChebyshevT[n, 3] + RootSum[-4 + 17 # - 10 #^2 + #^3 &, #^n &], {n, 0, 20}] (* Eric W. Weisstein, Sep 06 2025 *)
    LinearRecurrence[{39, -531, 2997, -6588, 5956, -2128, 256}, {3013, 51009, 864453, 14514449, 241137749, 3969473217, 64867543333}, {-2, 20}] (* Eric W. Weisstein, Sep 06 2025 *)
    CoefficientList[Series[-(1 - 26 x + 209 x^2 - 296 x^3 - 636 x^4 + 248 x^5 + 80 x^6)/((-1 + x) (-1 + 16 x) (1 - 12 x + 4 x^2) (-1 + 10 x - 17 x^2 + 4 x^3)), {x, 0, 20}], x] (* Eric W. Weisstein, Sep 06 2025 *)
  • PARI
    Vec((1 - 26*x + 209*x^2 - 296*x^3 - 636*x^4 + 248*x^5 + 80*x^6)/((1 - x)*(1 - 16*x)*(1 - 12*x + 4*x^2)*(1 - 10*x + 17*x^2 - 4*x^3)) + O(x^21)) \\ Andrew Howroyd, Dec 19 2024

Formula

G.f.: (1 - 26*x + 209*x^2 - 296*x^3 - 636*x^4 + 248*x^5 + 80*x^6)/((1 - x)*(1 - 16*x)*(1 - 12*x + 4*x^2)*(1 - 10*x + 17*x^2 - 4*x^3)). - Andrew Howroyd, Dec 19 2024
a(n) = 39*a(n-1)-531*a(n-2)+2997*a(n-3)-6588*a(n-4)+5956*a(n-5)-2128*a(n-6)+256*a(n-7). - Eric W. Weisstein, Sep 06 2025

Extensions

a(0)-a(2) prepended and a(7) onwards from Andrew Howroyd, Dec 19 2024

A379550 Number of minimal edge covers in the n-trapezohedral graph.

Original entry on oeis.org

1, 9, 49, 189, 651, 2138, 6847, 21805, 69781, 225260, 734119, 2413746, 7995417, 26639534, 89150537, 299309821, 1007213417, 3394930835, 11456074815, 38688727608, 130728462411, 441894675073, 1494097644221, 5052606384210, 17088501738431, 57800015328528, 195513178028053
Offset: 1

Views

Author

Eric W. Weisstein, Dec 25 2024

Keywords

Comments

The sequence has been extended to n=1 using the recurrence. - Andrew Howroyd, May 29 2025

Crossrefs

Cf. A356213.

Formula

G.f.: x*(1 - 4*x + 4*x^2 - 29*x^3 + 150*x^4 - 334*x^5 + 507*x^6 - 525*x^7 + 296*x^8 - 153*x^9 - 11*x^10 + 26*x^11 - 58*x^12 + 9*x^13 - 16*x^14 + 2*x^15 - x^16)/((1 - 2*x - x^3)^2*(1 - 2*x + x^2 - x^3)^3*(1 - 3*x - x^2 - x^3)). - Andrew Howroyd, May 29 2025

Extensions

a(1)-a(2) and a(8) onwards from Andrew Howroyd, May 29 2025
Showing 1-2 of 2 results.