[X/Fe] ratios in the H-box for the four considered cases (from left to right). The [¹²C/¹³C] ratio is also shown (i.e. ¹²C/¹³C ratio relative to the sun, in logarithm). The red points show the CEMP-no stars of Table 1 with [Fe/H] =−3.8 ± 0.3. The abundance patterns in the box at t = 0 are represented by black lines with squares and the patterns at the end of the simulation by black lines with triangles. The lower and upper black dotted lines represent the final composition in the H-box when the rates of injection are divided and multiplied by 10², respectively. The green pattern on the second (third) panel shows the composition in the hydrogen burning shell at the end of the core helium burning phase of a complete 20 M_⊙ stellar model at 30% (70%) of the critical velocity on the ZAMS. Density and temperature in the box are ρ = 1 g cm^-3 and T₆ = 50 MK.