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A120581
Hankel transform of sum{k=0..n, C(2k,k)*2^k}.
0
1, 4, -64, -28672, -17825792, -24696061952, -4398046511104, 6413125869375586304, 1279761316857673852911616, 565738597953418785628899770368, 372547299599873882347063111621541888, -5264848781000759906705331926184317767647232
OFFSET
0,2
FORMULA
a(n)=4^(n+C(n,2))(-1)^n*sum{k=0..n, C(n+k,2k)(-2)^(n-k)}; a(n)=8^n*4^C(n,2)*sum{k=0..n, C(n+k,2k)(-2)^(-k)}; a(n)=4^n*4^C(n,2)(-1)^n*A087168(n);
CROSSREFS
Cf. A120580.
Sequence in context: A229867 A362383 A051191 * A146520 A030176 A033635
KEYWORD
easy,sign
AUTHOR
Paul Barry, Jun 15 2006
STATUS
approved