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A234460
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Imaginary part of the product of all the integer complex numbers in the square [1,1] to [n,n].
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2
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OFFSET
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1,3
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LINKS
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Andrew Howroyd, Table of n, a(n) for n = 1..28
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FORMULA
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For n even, a(n) = 0, and for n odd, a(n) = A234459(n). - Michel Marcus, Dec 31 2013
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EXAMPLE
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For n = 2, we have (1 + i)(1 + 2i)(2 + i)(2 + 2i) which gives -20 + 0i, so a(2) = 0.
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MATHEMATICA
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Table[Im[Times@@Flatten[Table[a + b I, {a, n}, {b, n}]]], {n, 20}]
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PROG
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(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 + "<br>");
}
(PARI) a(n) = imag(prod(i=1, n, prod(j=1, n, i+I*j))); \\ Michel Marcus, Dec 31 2013
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CROSSREFS
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Cf. A000142, A234459.
Sequence in context: A276144 A234032 A290339 * A253745 A253752 A252317
Adjacent sequences: A234457 A234458 A234459 * A234461 A234462 A234463
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KEYWORD
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nonn
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AUTHOR
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Jon Perry, Dec 26 2013
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STATUS
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approved
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