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 1-4 of 4 results.

A000722 Number of invertible Boolean functions of n variables: a(n) = (2^n)!.

Original entry on oeis.org

1, 2, 24, 40320, 20922789888000, 263130836933693530167218012160000000, 126886932185884164103433389335161480802865516174545192198801894375214704230400000000000000
Offset: 0

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Comments

These are invertible maps from {0,1}^n to {0,1}^n, or in other words permutations of the 2^n binary vectors of length n.
2^n-th order derivative of n-th Mandelbrot iterate. Example: a(2) = 24, after one iterate in the Mandelbrot(z(n+1) = z(n)^2 + c) we have the function z(2) = z^4 + 2*c*z^2 + c^2 + c, for which the 4th-order derivative is 24. - Bert van den Bosch (zeusooooo(AT)hotmail.com), Sep 07 2003

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Mathematica
    a[n_] := Factorial[2^n]; Table[a[n],{n,0,6}] (* James C. McMahon, Dec 06 2023 *)
  • PARI
    atonfact(a,n) = {sr=0; for(x=1,n, y =(a^x)!; sr+=1.0/y; print1(y" "); ); print(); print(sr) }

Formula

a(n) = (2^n)!.
Sum of reciprocals = 0.54169146825401604874... - Cino Hilliard, Feb 08 2003

A000652 Invertible Boolean functions of n variables.

Original entry on oeis.org

1, 1, 6, 924, 81738720000, 256963707943061374889193111552000, 30978254928194376001814792318154658399138184007229852126545533479881553257431040000000
Offset: 0

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Comments

Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of (C_2)^n on both domain and range.

References

  • M. A. Harrison, Introduction to Switching and Automata Theory. McGraw Hill, NY, 1965, p. 154, problem 12.
  • C. S. Lorens, Invertible Boolean functions, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Formula

A000652: n->2^(-2*n)*( (2^n)! + (2^n-1)^2 * ( (2^(n-1))! )*2^(2^(n-1)));

Extensions

More terms from Vladeta Jovovic, Feb 23 2000

A001038 Invertible Boolean functions with GL(n,2) acting on the domain and range.

Original entry on oeis.org

2, 2, 10, 52246, 2631645209645100680144, 312242081385925594286511113384607360432260178128338777217975928751832
Offset: 1

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Comments

The Lorens paper gives the incorrect value a(5)=2631645209645100680142. - Sean A. Irvine, Feb 27 2012

References

  • C. S. Lorens, Invertible Boolean functions, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Extensions

Corrected and extended by Sean A. Irvine, Feb 26 2012

A128904 Number of AGL(n,2), AGL(n,2) double cosets in S(F_2^n).

Original entry on oeis.org

1, 1, 4, 302, 2569966041123938084
Offset: 1

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Author

Marcus Brinkmann (marcus.brinkmann(AT)rub.de), Apr 11 2007

Keywords

References

  • C. S. Lorens, Invertible Boolean functions, IEEE Trans. Electron. Computers, EC-13 (1964), 529-541.
  • Xiang-dong Hou (xhou(AT)euler.math.wright.edu), Affinity of Permutations of F_2^n, Proc. of the Workshop on Coding and Cryptography, pages 273-280, 2003

Crossrefs

Cf. A001537.
Showing 1-4 of 4 results.