A028402 Number of types of Boolean functions of n variables under a certain group.

6, 20, 72, 272, 1056, 4160, 16512, 65792, 262656, 1049600, 4196352, 16781312, 67117056, 268451840, 1073774592, 4295032832, 17180000256, 68719738880, 274878431232, 1099512676352, 4398048608256, 17592190238720, 70368752566272, 281474993487872, 1125899940397056

Offset: 2

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 2..300
• I. Strazdins, Universal affine classification of Boolean functions, Acta Applic. Math. 46 (1997), 147-167.
• Index entries for sequences related to Boolean functions
• Index entries for linear recurrences with constant coefficients, signature (6,-8).

Crossrefs

Essentially the same as A063376.

Programs

Magma

[2^(n-1)*(2^(n-1)+1): n in [2..30]]; // Vincenzo Librandi, Jan 08 2020

Mathematica

Table[2^(n-1) (2^(n-1) + 1), {n, 2, 30}] (* Vincenzo Librandi, Jan 08 2020 *)

Formula

a(n) = 2^(n-1) * (2^(n-1)+1). - Sean A. Irvine, Jan 07 2020

From Chai Wah Wu, Dec 29 2021: (Start)

a(n) = 6*a(n-1) - 8*a(n-2) for n > 3.

G.f.: x^2*(6 - 16*x)/((2*x - 1)*(4*x - 1)). (End)

Extensions

a(6) corrected and more terms from Sean A. Irvine, Jan 07 2020