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 A216206 a(n) = product_{i=1..n} ((-2)^i-1). 2
 1, -3, -9, 81, 1215, -40095, -2525985, 325852065, 83092276575, -42626337882975, -43606743654283425, 89350217747626737825, 365889141676531491393375, -2997729737755822508985921375, -49111806293653640164716349886625, 1609344780436736134557590069434814625 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Signed partial products of A062510. This implies that all terms from a(1) on are multiples of 3. LINKS Table of n, a(n) for n=0..15. FORMULA A015109(n,k) = a(n)/(a(k)*a(n-k)). a(n) = (-3)^n*A015013(n) for n>0, a(0)=1. [Bruno Berselli and Alonso del Arte, Mar 13 2013] MAPLE A216206 := proc(n) mul( (-2)^i-1, i=1..n) ; end proc: MATHEMATICA Table[(-1)^n QPochhammer[-2, -2, n], {n, 0, 15}] (* Bruno Berselli, Mar 13 2013 *) CROSSREFS Cf. A027871, A005329. Sequence in context: A121858 A215114 A032108 * A038062 A218149 A011764 Adjacent sequences: A216203 A216204 A216205 * A216207 A216208 A216209 KEYWORD sign,easy AUTHOR R. J. Mathar, Mar 12 2013 STATUS approved

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Last modified February 26 04:47 EST 2024. Contains 370335 sequences. (Running on oeis4.)