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.

A305000 Number of labeled antichains of finite sets spanning some subset of {1,...,n} with singleton edges allowed.

Original entry on oeis.org

1, 2, 8, 72, 1824, 220608, 498243968, 309072306743552, 14369391925598802012151296, 146629927766168786239127150948525247729660416
Offset: 0

Views

Author

Gus Wiseman, May 23 2018

Keywords

Comments

Only the non-singleton edges are required to form an antichain.
Number of non-degenerate unate Boolean functions of n or fewer variables. - Aniruddha Biswas, May 11 2024

Examples

			The a(2) = 8 antichains:
  {}
  {{1}}
  {{2}}
  {{1,2}}
  {{1},{2}}
  {{1},{1,2}}
  {{2},{1,2}}
  {{1},{2},{1,2}}
		

Crossrefs

Formula

Binomial transform of A304999.
Inverse binomial transform of A245079. - Aniruddha Biswas, May 11 2024

Extensions

a(5)-a(8) from Gus Wiseman, May 31 2018
a(9) from Aniruddha Biswas, May 11 2024

A372495 Number of inequivalent unate functions of n or fewer variables.

Original entry on oeis.org

2, 4, 10, 34, 200, 3466, 829744
Offset: 0

Views

Author

Aniruddha Biswas, May 03 2024

Keywords

Comments

A Boolean function is unate in a variable if it is either nondecreasing or nonincreasing with respect to that variable. Therefore in the circuit representation of unate functions, each variable appears either in its original form or in complemented form. Thus x⊕y = (x∧¬y)∨(¬x∧y) is not a unate function.
Moreover, two Boolean functions are said to be equivalent if they are equivalent under the permutation of variables. For example, f(x,y)=x is equivalent to f(x,y)=y under the permutation of input variables.

Examples

			The list of all 2-variable inequivalent unate functions f(x,y) is 0,1,x,¬x,x∧y,¬x∧y,¬x∧¬y,x∨y,¬x∨y,¬x∨¬y. So a(2)=10.
		

Crossrefs

A373697 Number of nondegenerate balanced unate functions of n or fewer variables.

Original entry on oeis.org

0, 2, 0, 8, 256, 16832, 31287424, 10393552784640
Offset: 0

Views

Author

Aniruddha Biswas, Jun 13 2024

Keywords

Crossrefs

A374399 Number of inequivalent nondegenerate unate functions of n or fewer variables.

Original entry on oeis.org

2, 2, 6, 24, 166, 3266, 826308
Offset: 0

Views

Author

Aniruddha Biswas, Jul 07 2024

Keywords

Comments

A Boolean function is degenerate on some variable if its output does not depend on the variable, and it is said to be non-degenerate if it is not degenerate on any variable.
Appears to be (essentially) the partial sums of A304997. - N. J. A. Sloane, Jul 26 2024

Crossrefs

A373690 Number of balanced unate functions of n or fewer variables.

Original entry on oeis.org

0, 2, 4, 14, 296, 18202, 31392428, 10393772159334
Offset: 0

Views

Author

Aniruddha Biswas, Jun 13 2024

Keywords

Crossrefs

Extensions

Typo in a(3) corrected by Andrei Zabolotskii, Jul 29 2025

A374400 Number of balanced inequivalent unate functions of n or fewer variables.

Original entry on oeis.org

0, 2, 2, 6, 24, 254, 50172
Offset: 0

Views

Author

Aniruddha Biswas, Jul 07 2024

Keywords

Comments

A Boolean function is said to be balanced if it takes the values 0 and 1 an equal number of times.

Crossrefs

A374401 Number of balanced inequivalent nondegenerate unate functions of n or fewer variables.

Original entry on oeis.org

0, 2, 0, 4, 18, 230, 49918
Offset: 0

Views

Author

Aniruddha Biswas, Jul 07 2024

Keywords

Crossrefs

Showing 1-7 of 7 results.