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.

A367532 The number of ways of tiling the n X n grid up to 90-degree rotation by a tile that is not fixed under 180-degree rotation.

Original entry on oeis.org

1, 70, 65536, 1073758336, 281474976710656, 1180591620734591303680, 79228162514264337593543950336, 85070591730234615870455337878516924416, 1461501637330902918203684832716283019655932542976, 401734511064747568885490523085607563280607806359022338048000
Offset: 1

Views

Author

Peter Kagey, Dec 11 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[{256^(m^2 - m), 4^(m^2 - 1)*(2 + 4^m^2 + 64^m^2)}, {m, 1, 5}] // Flatten

Formula

a(2*n-1) = 256^(n^2 - n).
a(2*n) = 4^(n^2 - 1)*(2 + 4^n^2 + 64^n^2).

A368144 Number of ways of tiling the n X n torus up to 90-degree rotations of the square by a tile that is fixed only under 180-degree rotation of the square.

Original entry on oeis.org

1, 4, 24, 1155, 337600, 477339104, 2872202028544, 72057595967327280, 7462505059899321934848, 3169126500571074529208754688, 5492677668532710795071525279789056, 38716571525226776289479030777851808143360, 1106936151351216411420552029913564174524281470976
Offset: 1

Views

Author

Peter Kagey, Dec 16 2023

Keywords

Crossrefs

Programs

  • Mathematica
    A368144[n_] := 1/(4 n^2)*(DivisorSum[n, Function[d, DivisorSum[n, Function[c, EulerPhi[c] EulerPhi[d] 2^(n^2/LCM[c, d])]]]] + n^2*If[OddQ[n], 2^((n^2 + 1)/2), 7/4*2^(n^2/2) + 2^(n^2/4)])
Showing 1-2 of 2 results.