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.

A005736 Number of degenerate fanout-free Boolean functions of n variables using And, Or and Not gates.

Original entry on oeis.org

0, 2, 6, 32, 314, 4892, 104518, 2814520, 91069042, 3434371508, 147755228670, 7137203824016, 382309275191786, 22484502178536140, 1440083130444110134, 99761235465965943400, 7431676025141300550370, 592372327653418546022756
Offset: 0

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Author

Keywords

References

  • J. P. Hayes, Enumeration of fanout-free Boolean functions, J. ACM, 23 (1976), 700-709.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Formula

a(n) = Sum_{k=0..n-1} binomial(n, k) * s(k) where s(0)=2 and s(n) = A005640(n + 1) otherwise. - Sean A. Irvine, Jul 21 2016
a(n) = A005737(n) - A224766(n). - Andrew Howroyd, Mar 29 2025

Extensions

More terms from Sean A. Irvine, Jul 21 2016
Name clarified by Andrew Howroyd, Apr 03 2025

A224766 Number of non-degenerate fanout-free Boolean functions of n variables using And, Or and Not gates.

Original entry on oeis.org

2, 2, 8, 64, 832, 15104, 352256, 10037248, 337936384, 13126565888, 577818263552, 28425821618176, 1545553369366528, 92034646352592896, 5956917762776367104, 416397789920380321792, 31262503202358260924416, 2508985620606225641111552, 214348807882902869374926848
Offset: 0

Views

Author

N. J. A. Sloane, Apr 30 2013

Keywords

Comments

Apart from initial term and offset, same as A005640, which is the main entry for this sequence.

References

  • J. P. Hayes, Enumeration of fanout-free Boolean functions, J. ACM, 23 (1976), 700-709.

Crossrefs

Programs

  • PARI
    seq(n) = Vec(2*serlaplace(1 - x + serreverse((1 + 2*x - exp(x + O(x*x^n)))/2))) \\ Andrew Howroyd, Mar 28 2025

Formula

a(n) = 2*A005172(n) for n > 0. - Andrew Howroyd, Mar 28 2025

Extensions

Name clarified and a(19) onwards from Andrew Howroyd, Mar 28 2025
Showing 1-2 of 2 results.