A057157 Number of non-invertible functions from {0,1}^n to {0,1}^n.

0, 2, 232, 16736896, 18446723150919663616, 1461501637330639787366751139186115801643772542976

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10

Formula

a(n) = (2^n)^(2^n) - (2^n)! = A057156(n) - A000722(n) = A036679(A000079(n)).

Mathematica

Table[(2^n)^(2^n) - (2^n)!, {n, 0, 5}] (* G. C. Greubel, Nov 08 2018 *)

Prog

(Magma) [(2^n)^(2^n)-Factorial(2^n): n in [0..5]]; // Vincenzo Librandi, Aug 22 2011
(PARI) vector(6, n, n--; (2^n)^(2^n) - (2^n)!) \\ G. C. Greubel, Nov 08 2018

Crossrefs

Cf. A057156, A000722, A036679, A000079.

Sequence in context: A012526 A012668 A012530 * A139963 A124046 A101146

Adjacent sequences: A057154 A057155 A057156 * A057158 A057159 A057160

Keyword

nonn,easy

Author

Henry Bottomley, Aug 15 2000

Status

approved