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 1-7 of 7 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

A000654 Invertible Boolean functions of n variables.

Original entry on oeis.org

1, 2, 52, 142090700, 17844701940501123640681816160, 59757436204078657410908164193971330396709572693816353610758085074676243846093824
Offset: 1

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Comments

Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of permutation and complementation of variables on domain and range. - Sean A. Irvine, Mar 16 2011

References

  • M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28.
  • 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).

Programs

  • Mathematica
    cyclify =
      Function[{x},
       Sort@Tally[Length /@ PermutationCycles[x + 1, Identity]]];
    totalweight =
      Function[{c}, Product[(x[[1]]^x[[2]]) ( x[[2]]!), {x, c}]];
    perms = Function[{n},
       Flatten[Table[
         FromDigits[Permute[IntegerDigits[BitXor[x, a], 2, n], sigma],
          2], {sigma, Permutations[Range[n]]}, {a, 0, 2^n - 1}, {x, 0,
          2^n - 1}], 1]];
    countit =
      Function[{n},
       Sum[totalweight[x[[1]]] (x[[2]]^2), {x,
          Tally[cyclify /@ perms[n]]}]/((2^n) (n!))^2];
    Table[countit[n], {n, 1, 5}] (*  Adam P. Goucher, Feb 12 2021 *)

Extensions

More terms from Sean A. Irvine, Mar 15 2011

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

A000723 Invertible Boolean functions of n variables.

Original entry on oeis.org

1, 3, 840, 54486432000, 68523655451482690147713024000000, 2753622660283944533494648206058191857701074569760095316814277221684346880000000000000
Offset: 1

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Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of (C_2)^n on domain and permutation of variables on range. - Sean A. Irvine, Mar 15 2011
Also the number of distinct adjacency matrices of the n-hypercube graph Q_n. - Eric W. Weisstein, Mar 31 2017

References

  • M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28.
  • 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).

Programs

Formula

a(n) = (2^n-1)!/n!. - Sean A. Irvine, Mar 15 2011

Extensions

More terms from Sean A. Irvine, Mar 14 2011

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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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

A000724 Invertible Boolean functions of n variables.

Original entry on oeis.org

1, 3, 196, 3406687200, 2141364232858913975435172249600, 43025354066936633335853878219659247776604712057098163541301459387254457761792000000
Offset: 1

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Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of (C_2)^n on domain and F_n=[S_2]^(S_n) on range. - Sean A. Irvine, Mar 16 2011
Technical report version of Harrison's paper contains incorrect value for a(4). - Sean A. Irvine, Mar 16 2011

References

  • M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28.
  • 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).

Programs

  • Mathematica
    Table[((2^n)! + (2^n - 1) (2^(n - 1))! 2^(2^(n - 1)) * (n! * Sum[ (2^(n - 2 k) - 1)/((n - 2 k)!*k!), {k, 0, Floor[(n - 1)/2]}]))/(n! 2^(2 n)), {n, 6}] (* Michael De Vlieger, Aug 20 2017 *)

Formula

a(n) = ((2^n)! + (2^n-1) * (2^(n-1))! * 2^(2^(n-1)) * b(n)) / (n! * 2^(2*n)) where b(n) = n! * Sum_{k=0..floor((n-1)/2)} (2^(n-2*k)-1) / ((n - 2*k)! * k!). - Sean A. Irvine, Aug 20 2017

Extensions

More terms from Sean A. Irvine, Mar 15 2011

A000725 Invertible Boolean functions of n variables.

Original entry on oeis.org

1, 2, 154, 2270394624, 571030462095782973206774552784, 3824475917061034074298122508414160251634847335755905881951011420229530501911521280
Offset: 1

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Author

Keywords

Comments

Equivalence classes of invertible maps from {0,1}^n to {0,1}^n, under action of permutation of variables on the domain and permutation and complementation of the range. [Sean A. Irvine, Mar 16 2011]

References

  • M. A. Harrison, The number of classes of invertible Boolean functions, J. ACM 10 (1963), 25-28.
  • 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).

Extensions

More terms from Sean A. Irvine, Mar 15 2011
a(6) corrected by Sean A. Irvine, May 29 2013
a(5) corrected by Sean A. Irvine, Jun 03 2013
Showing 1-7 of 7 results.