A075464 - OEIS

%I #36 Feb 16 2025 08:32:47

%S 1,4,5,4,15,28,33,40,25,44,55,72,105,56,117,104,147,188,141,224,245,

%T 276,231,270,353,356,405,416,345,376,553,428,469,520,563,600,761,772,

%U 561,696,891,940,953,772,1069,1188,971,1096,1165,1220,1317,1256,1487,1400

%N a(n) is the minimal number of nontrivial switch flippings needed to solve the all-ones lights out problem on an n X n square.

%C For squares having multiple possible solutions (see A075462, A075463), there may be nontrivial solutions involving *more* than this number of flips.

%D See A075462 for references.

%H Zhao Hui Du, <a href="/A075464/b075464.txt">Table of n, a(n) for n = 1..78</a> (terms 1..60 from Max Alekseyev)

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LightsOutPuzzle.html">Lights Out Puzzle</a>

%H Zhao Hui Du, <a href="/A075464/a075464.c.txt">C code for the problem</a> (please compile it using the latest gcc with option -O3 -msse4.2)

%Y Cf. A075462, A075463.

%K nonn,nice

%O 1,2

%A _Eric W. Weisstein_, Sep 17 2002

%E a(26)-a(29) from _Les Reid_, Sep 09 2007

%E a(30)-a(38) from _Max Alekseyev_, Sep 17 2009

%E Extended by _Max Alekseyev_, Sep 20 2009