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A234460 Imaginary part of the product of all the integer complex numbers in the square [1,1] to [n,n]. 1
1, 0, 7800, 0, 2787453552000000, 0, 3108366378804858902744832000000000000, 0, 165290679439545659068950724771043004678057040281600000000000000000000, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..10.

FORMULA

It appears that 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 + "<br>");

}

(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 February 20 07:09 EST 2018. Contains 299359 sequences. (Running on oeis4.)