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Problem 207

Algebra Difficulty 1.4 Multiple choice CEMC Gauss (Grade 8) · Canada · 2024

In the sequence $1, 3, 4, 7,
\ldots, each number beginning with the 4$ is the sum of the two numbers before
it. This means that the next number in the sequence is 4+7=114+7=11. The smallest number greater than
100100 that appears in the sequence
is

Pick one

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Official solution

Continuing the sequence, we get 11, 33, 44, 77, 1111, 1818, 2929, 4747, 7676, 123123, and so the smallest number greater
than 100100 that appears in the
sequence is 123123.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.