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 A234460 Imaginary part of the product of all the integer complex numbers in the square [1,1] to [n,n]. 2
 1, 0, 7800, 0, 2787453552000000, 0, 3108366378804858902744832000000000000, 0, 165290679439545659068950724771043004678057040281600000000000000000000, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Andrew Howroyd, Table of n, a(n) for n = 1..28 FORMULA For n even, a(n) = 0, and for n odd, a(n) = A234459(n). - Michel Marcus, Dec 31 2013 EXAMPLE For n = 2, we have (1 + i)(1 + 2i)(2 + i)(2 + 2i) which gives -20 + 0i, so a(2) = 0. MATHEMATICA Table[Im[Times@@Flatten[Table[a + b I, {a, n}, {b, n}]]], {n, 20}] PROG (JavaScript) function cNumber(x, y) { return [x, y]; } function cMult(a, b) { return [a[0] * b[0] - a[1] * b[1], a[0] * b[1] + a[1] * b[0]]; } for (i = 1; i < 10; i++) { c = cNumber(1, 0); for (j = 1; j <= i; j++) for (k = 1; k <= i; k++) c = cMult(c, cNumber(j, k)); document.write(c + "
"); } (PARI) a(n) = imag(prod(i=1, n, prod(j=1, n, i+I*j))); \\ Michel Marcus, Dec 31 2013 CROSSREFS Cf. A000142, A234459. Sequence in context: A276144 A234032 A290339 * A253745 A253752 A252317 Adjacent sequences:  A234457 A234458 A234459 * A234461 A234462 A234463 KEYWORD nonn AUTHOR Jon Perry, Dec 26 2013 STATUS approved

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Last modified January 23 07:12 EST 2019. Contains 319374 sequences. (Running on oeis4.)