Search: id:A008794 Results 1-1 of 1 results found. %I A008794 %S A008794 0,0,1,1,4,4,9,9,16,16,25,25,36,36,49,49,64,64,81,81,100,100, %T A008794 121,121,144,144,169,169,196,196,225,225,256,256,289,289, %U A008794 324,324,361,361,400,400,441,441,484,484,529,529,576,576 %N A008794 Squares repeated. %C A008794 Also number of non-attacking kings on n-2 X n-2 board (cf. A030978). - Koksal Karakus (karakusk(AT)hotmail.com), May 27 2002 %C A008794 Maximum number of 2 X 2 tiles that fit on an n X n board. - Jon Perry (perry(AT)globalnet.co.uk), Aug 10 2003 %C A008794 (n)-(1) + (n-1) -(2) +(n-3)-(3)+ ... + (n-r) -(r)... n terms. e.g. 5-1+4-2+3=9 6-1+5-2+4-3=9 7-1+6-2+5-3+4 =16 8-1+7-2+6-3+5-4=16 - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jul 24 2005 %C A008794 The smallest possible number of white cells in a solution to an n X n nurikabe grid. [From Tanya Khovanova (tanyakh(AT)yahoo.com), Feb 24 2009] %H A008794 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics. %F A008794 a(n)=[floor(n/2)]^2 %F A008794 a(n)=(2n-1)(-1)^n/8+(2n^2-2n +1)/8; a(n+1)=sum{k=0..n, k(1-(-1)^k)/2}. - Paul Barry (pbarry(AT)wit.ie), May 31 2003 %F A008794 a(n)={sqrt[sum_{j=0..n}(j+1)*(cos(j*Pi)+1)/2]-1}^2 with n>=0. - Paolo P. Lava (ppl(AT)spl.at), Dec 04 2006 %p A008794 G.f.: x^2*(1+x^2)/((1-x^2)^2*(1-x)). %Y A008794 Cf. A086832. %Y A008794 Sequence in context: A014694 A065730 A145445 this_sequence A075709 A116682 A088190 %Y A008794 Adjacent sequences: A008791 A008792 A008793 this_sequence A008795 A008796 A008797 %K A008794 nonn %O A008794 0,5 %A A008794 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.002 seconds