A005756 Number of non-degenerate fanout-free Boolean functions of n variables having AND rank 2.

4, 24, 304, 5440, 125824, 3566080, 119614464, 4633387008, 203524112384, 9995546722304, 542730361241600, 32281981804347392, 2087454641985945600, 145797871819529650176, 10938609224992417644544, 877346430770422497673216, 74913579745878635293179904, 6784650500440844952024383488

Offset: 2

Author

N. J. A. Sloane

Keywords

• nonn

References

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

Links

• Andrew Howroyd, Table of n, a(n) for n = 2..200
• J. P. Hayes, Enumeration of fanout-free Boolean functions, J. ACM, 23 (1976), 700-709.
• Index entries for sequences related to Boolean functions

Crossrefs

Column 2 of A225171.

Formula

Hayes (1976, Theorem 3) gives a recurrence.

Extensions

More terms from Sean A. Irvine, Aug 26 2016

a(18) onwards from Andrew Howroyd, Mar 28 2025