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A138176 Hankel transform of A138175. 1
1, -4, 144, -43264, 106832896, -2155963622400, 354617391605760000, -474686810341051524710400, 5166329306435680284163452174336, -456900249341808231214942590547243565056 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
When aerated, gives Hankel transform of A138175. sqrt(abs(a(n))/2^n=A005156(n).
LINKS
FORMULA
a(n)=(-1)^n*product{k=1..n, (6k-2)!(2k-1)!/((4k-1)!(4k-2)!)}^2
CROSSREFS
Sequence in context: A122747 A069135 A186081 * A203424 A055209 A239350
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 03 2008
STATUS
approved

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Last modified July 20 15:46 EDT 2024. Contains 374459 sequences. (Running on oeis4.)