A000883 - OEIS

%I M1956 N0774 #34 Sep 08 2022 08:44:28

%S 2,9,443,11211435,24019199779842731,

%T 221537999297485986455406144733751979,

%U 37692737381938865697777013349182261812327566685142592258699083037385861803

%N Number of switching networks with C(2,n) acting on the domain and AG(2,2) acting on the range.

%D M. A. Harrison, On the number of classes of switching networks, J. Franklin Instit., 276 (1963), 313-327.

%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Vincenzo Librandi, <a href="/A000883/b000883.txt">Table of n, a(n) for n = 1..10</a>

%H <a href="/index/Sw#switching">Index entries for sequences related to switching networks</a>

%F a(n) = (4^(2^n) - 4*2^(2^n) + 8*2^n + 10*2^(n+2^n))/(24*2^n). - _Sean A. Irvine_, Jan 24 2012

%t Table[(4^(2^n)-4*2^(2^n)+8*2^n+10*2^(n+2^n))/(24*2^n),{n,0,11}] (* _Vincenzo Librandi_, Mar 28 2012 *)

%o (Magma) [(4^(2^n)-4*2^(2^n)+8*2^n+10*2^(n+2^n))/(24*2^n):n in [1..11]]; // _Vincenzo Librandi_, Mar 28 2012

%o (PARI) a(n)=my(N=2^n);(2^(2*N-n)-4<<(N-n)+8+10<<N)/24 \\ _Charles R Greathouse IV_, Mar 28 2012

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_

%E More terms from _Sean A. Irvine_, Jan 23 2012