A290495 The number of self-inverse Boolean functions of n variables.

1, 2, 10, 764, 46206736, 22481059424730751232, 135041388282796985771272553475002706667235246080, 5391278204075391354568253023229655921370142671388586075937736698667444395805138812903649656844450530044101525504

Offset

0,2

Links

Table of n, a(n) for n=0..7.

Formula

a(n) = Sum_{k=0..2^(n-1)} (2^n)!/((2^n-2*k)! * k! * 2^k).

a(n) = A000085(2^n).

Mathematica

Table[Sum[(2^n)!/((2^n - 2 k)!*k!*2^k), {k, 0, 2^(n - 1)}], {n, 0, 7}] (* Michael De Vlieger, Aug 04 2017 *)

Prog

(PARI) a(n) = sum(k=0, 2^(n-1), (2^n)!/((2^n-2*k)!*k!*2^k)) \\ Felix Fröhlich, Aug 04 2017

Crossrefs

Cf. A000722 (invertible Boolean functions).

Sequence in context: A028582 A222420 A263921 * A255587 A137890 A074333

Adjacent sequences: A290492 A290493 A290494 * A290496 A290497 A290498

Keyword

nonn

Author

Sean A. Irvine, Aug 04 2017

Status

approved