02.16 · Problem

The Robot Chant

Medium Simulation: group equal neighbours (look-and-say) Pro

This problem is part of solulu Pro

A robot chants a sequence: the first chant is 1. Every next chant *describes the previous one* by reading its runs: 1 → "one 1" → 11; 11 → "two 1s" → 21; 21 → "one 2, one 1" → 1211; and so on. What is the n-th chant?

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Item 36 of 94 · updated 2026-10-12