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A302661 Real part of Product_{k=1..n} (k+(n-k+1)i), with i=sqrt(-1). 3
1, 1, 0, -20, -221, -1560, 0, 272000, 6356025, 84086080, 0, -40560998400, -1449723503125, -28152429760000, 0, 26582971351040000, 1279483892211136625, 32774236110420480000, 0, -51128938217766256640000, -3094745459011904478178125, -98456230888859903488000000, 0, 229377281607595274010624000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
a(n) = 0 for n mod 4 = 2 (A016825). - Michel Marcus, Apr 11 2018
LINKS
MAPLE
seq(Re(mul(k+(n-k+1)*I, k=1..n)), n=0..30); # Muniru A Asiru, Apr 11 2018
PROG
(PARI) {a(n) = real(prod(k=1, n, k+(n-k+1)*I))}
CROSSREFS
Imaginary part: A302662.
Sequence in context: A140354 A155673 A000833 * A178261 A054329 A112503
KEYWORD
sign
AUTHOR
Seiichi Manyama, Apr 11 2018
STATUS
approved

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Last modified May 25 14:05 EDT 2024. Contains 372788 sequences. (Running on oeis4.)