Question Number 33848 by prof Abdo imad last updated on 26/Apr/18
$${let}\:{w}_{{n}} =\:\frac{{H}_{{n}} ^{\mathrm{2}} }{{n}}\:\:\:{with}\:{H}_{{n}} =\sum_{{k}=\mathrm{1}} ^{{n}} \:\frac{\mathrm{1}}{{k}} \\ $$$${study}\:{the}\:{convergence}\:{of}\:\sum_{{n}=\mathrm{1}} ^{\infty} \:{w}_{{n}} {x}^{{n}} \:\:. \\ $$