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 A098106 Hankel transform of sequence (b(n)) where b(n)=sum(i=0,n,binomial(2*i,i)). 0
 1, 3, 6, -8, -72, -144, 64, 960, 1920, -512, -10752, -21504, 4096, 110592, 221184, -32768, -1081344, -2162688, 262144, 10223616, 20447232, -2097152, -94371840, -188743680, 16777216, 855638016, 1711276032, -134217728, -7650410496, -15300820992, 1073741824, 67645734912, 135291469824 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS J. W. Layman, The Hankel Transform and Some of its Properties, J. Integer Sequences, 4 (2001), #01.1.5. FORMULA a(3n)=(-8)^n; a(3n+1)=3*(-8)^n*(2*n+1); a(3n+2)=6*(-8)^n*(2*n+1) PROG (PARI) a(n)=if(n<0, 0, if(n%3, if(n%3-1, 6*(-8)^floor(n/3)*(2*floor(n/3)+1), 3*(-8)^floor(n/3)*(2*floor(n/3)+1)), (-8)^(n/3))) CROSSREFS Cf. A006134. Sequence in context: A038064 A093899 A137129 * A059361 A103268 A114157 Adjacent sequences:  A098103 A098104 A098105 * A098107 A098108 A098109 KEYWORD sign AUTHOR Benoit Cloitre, Sep 22 2004 STATUS approved

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