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A302662
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Imaginary part of Product_{k=1..n} (k+(n-k+1)i), with i=sqrt(-1).
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3
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0, 1, 5, 20, 0, -1560, -26825, -272000, 0, 84086080, 2484885325, 40560998400, 0, -28152429760000, -1180588763732625, -26582971351040000, 0, 32774236110420480000, 1780605230870046303125, 51128938217766256640000, 0, -98456230888859903488000000, -6569779608356896665959265625
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OFFSET
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0,3
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COMMENTS
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LINKS
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MAPLE
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seq(Im(mul(k+(n-k+1)*I, k=1..n)), n=0..30); # Muniru A Asiru, Apr 11 2018
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PROG
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(PARI) {a(n) = imag(prod(k=1, n, k+(n-k+1)*I))}
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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