Search: id:A099087 Results 1-1 of 1 results found. %I A099087 %S A099087 1,2,2,0,4,8,8,0,16,32,32,0,64,128,128,0,256,512,512,0,1024,2048,2048, 0, %T A099087 4096,8192,8192,0,16384,32768,32768,0,65536,131072,131072,0,262144,524288, %U A099087 524288,0,1048576,2097152,2097152,0,4194304,8388608,8388608,0,16777216 %V A099087 1,2,2,0,-4,-8,-8,0,16,32,32,0,-64,-128,-128,0,256,512,512,0,-1024,-2048, -2048,0, %W A099087 4096,8192,8192,0,-16384,-32768,-32768,0,65536,131072,131072,0,-262144, -524288, %X A099087 -524288,0,1048576,2097152,2097152,0,-4194304,-8388608,-8388608,0,16777216 %N A099087 G.f.: 1/(1-2*x+2*x^2). %C A099087 Yet another variation on A009545. %C A099087 Row sums of Krawtchouk triangle A098593. Partial sums of e.g.f. exp(x)cos(x), or 2^(n/2)cos(pi*n/2). See A009116. %C A099087 Binomial transform of A057077. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 04 2008] %C A099087 Partial sums of A146559 . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 01 2008] %H A099087 Index entries for sequences related to linear recurrences with constant coefficients %F A099087 E.g.f.: exp(x)(cos(x)+sin(x)); a(n)=2^(n/2)(cos(pi*n/4)+sin(pi*n/4)); a(n)=sum{k=0..n, sum{i=0..k, C(n-k, k-i)C(n, i)(-1)^(k-i)}}; a(n)=2a(n-1)-2a(n-2). %F A099087 a(n) = (1-I)^(n-1)+(1+I)^(n-1) where I=sqrt(-1). a(n) = 2 sum_{k=0,1, 2,..(n-1)/2} (-1)^k*binomial(n-1,2k) if n>0. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 18 2008 %F A099087 a(n)=Sum_{k, 0<=k<=n} A109466(n,k)*2^k. [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Oct 28 2008] %o A099087 (Other) sage: [lucas_number1(n,2,2) for n in xrange(1, 50)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009] %Y A099087 Cf. A009545. %Y A099087 Sequence in context: A100240 A072690 A108520 this_sequence A009545 A084102 A160125 %Y A099087 Adjacent sequences: A099084 A099085 A099086 this_sequence A099088 A099089 A099090 %K A099087 easy,sign %O A099087 0,2 %A A099087 Paul Barry (pbarry(AT)wit.ie), Sep 24 2004 %E A099087 Signs added by N. J. A. Sloane (njas(AT)research.att.com), Nov 14, 2006 Search completed in 0.002 seconds