For an A={ai}i=0∞ sequence let SA={a0,a0+a1,a0+a1+a2,…} be the sequence of partial sums of the a0+a1+… series. Does there exist a non-identically zero sequence A such that all of the sequences A,SA,SSA,SSSA,… are convergent?(translated by Miklós Maróti) Miklos Schweitzerreal analysiscollege contests