Question

Dati exemple ce 4 numere naturale ce admit exact 8 divizori.
Va rog..repede..

Answer 1

$24- \{1,2,3,4,6,8,12,24\} \\ 40-\{1,2,4,5,8,10,20,40\} \\ 30-\{1,2,3,5,6,10,15,30\} \\ 128-\{1,2,4,8,16,32,64,128\} \\ \\ Am~gasit~numerele~utilizand~faptul~ca~un~numar~natural~n,~unde \\ \\ n=p_{1}^{r_1} \cdot p_2^{r_2} \cdot p_3 ^{r_3} \cdot ... \cdot p_k ^{r_k},~iar~p_1 ,~p_2,~p_3,...~p_k~sunt~numere~prime~are \\ \\ (r_1+1)(r_2+1)(r_3+1)...(r_k+1)~divizori~naturali.$

$Numerele~cu~exact~8~divizori~sunt~de~forma:~a^7;~b \cdot c^3~sau~ \\ d \cdot e \cdot f,~unde~a,b,c,d,e,f~sunt~numere~prime.$