Words without subwords

Task number: 3491

How many sequences of the letters A, B, D, E, I, K, M, N, R, Ů, Z exist such that by removing letters we are never left with any of the (Czech) words:

  • Variant

    BAR, DEN, RAZIE

  • Variant

    ARZEN, DRAK, DŮM, DŮRAZ

Difficulty level: Moderate task
Routine calculation training
Cs translation
Send comment on task by email