The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 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 FrÃ¶hlich, 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

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