login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A064436 Number of switching functions of n or fewer variables which cannot be realized as threshold gates. 5
0, 0, 2, 152, 63654, 4294872724, 18446744073694523482, 340282366920938463463374607423390140592, 115792089237316195423570985008687907853269984665640564039457583990351590086990 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

The corresponding systems of linear inequalities are not solvable: linearly non-separable truth or switching functions. Truth functions which ar "non-neurons" and are realizable only as two levels threshold gate networks.

LINKS

Wang Lan, Table of n, a(n) for n = 0...9

FORMULA

a(n)=2^(2^n)-A000609(n)

EXAMPLE

n=2: out of the 16 B^2 -> B^1 truth functions, 14 are linearly separable; the 2 exceptions are XOR and its negation: f[x,y]=!xz+x!y and !f[x,y]=xy+!x!y. So a(2)=2. With increasing n, the chance that a switching function belongs to this sequence tends to 1.

CROSSREFS

A000609.

Sequence in context: A113576 A102458 A206309 * A012605 A012602 A157087

Adjacent sequences:  A064433 A064434 A064435 * A064437 A064438 A064439

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Oct 01 2001

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 14:54 EST 2012. Contains 205822 sequences.