olymmath

AIME 2023a Problem 14

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The following analog clock has two hands that can move independently of each other. [asy] unitsize(2cm); draw(unitcircle,black+linewidth(2)); for (int i = 0; i < 12; ++i) { draw(0.9dir(30i)--dir(30i)); } for (int i = 0; i < 4; ++i) { draw(0.85dir(90i)--dir(90i),black+linewidth(2)); } for (int i = 1; i < 13; ++i) { label("\small" + (string) i, dir(90 - i * 30) * 0.75); } draw((0,0)--0.6dir(90),black+linewidth(2),Arrow(TeXHead,2bp)); draw((0,0)--0.4dir(90),black+linewidth(2),Arrow(TeXHead,2bp)); [/asy] Initially, both hands point to the number 1212. The clock performs a sequence of hand movements so that on each movement, one of the two hands moves clockwise to the next number on the clock face while the other hand does not move. Let NN be the number of sequences of 144144 hand movements such that during the sequence, every possible positioning of the hands appears exactly once, and at the end of the 144144 movements, the hands have returned to their initial position. Find the remainder when NN is divided by 10001000.

Dataset text AIME 1983 to 2026. Quoted with source.

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