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A290495 The number of self-inverse Boolean functions of n variables. 0
1, 2, 10, 764, 46206736, 22481059424730751232, 135041388282796985771272553475002706667235246080, 5391278204075391354568253023229655921370142671388586075937736698667444395805138812903649656844450530044101525504 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 16 18:13 EDT 2021. Contains 343949 sequences. (Running on oeis4.)