We know that:

Here's my program:

k = 100000;
ss = 1000;
Print["Initialization Done"];
Do[prt[i] = Prime[i], {i, 1, k}];
Print["Prime Geneneration Done"];
Do[prtsq[i] = prt[i]*prt[i], {i, 1, k}];
Print["Squaring Done"];
Do[thearr[i] = 1/prtsq[i], {i, 1, 100000}];
Print["Factorising Done"];
sum = 0;
Do[sum += N[thearr[i], ss], {i, 1, 100000}];
Print["Sum = ", sum];

And here's what I get for the sum:
0.4522473688277700954422164277522326096645066956889359406373748543156987039966
525643794108225095161389758244363445339660776113109242885808492718205416638194
526958800379786519866057949036856229177825278987902389864970540352844167196863
834688645075159015805935496856212223538491039364902103635445065361656745970932
905021125274435235568533828552570131338540212094414196757580439057169807537575
899440924188480149221835203239871132457344235369007243117411236106046262308444
576868350724155932530725321698618605264299442562165096782086212268498382688102

I get everything except the N and the ss usage.

And if Prime[] returns 0 if not prime, then why don't you get divide by zero error?
Tell me about Prime[]
Does prime return infinitywhen not prime?

For John, not, PrimeQ[] is for testing whatever a number is prime.
Prime[n] gives the n-th pime number:
Prime[1]=2
Prime[2]=3
Prime[3]=5
...

Okay, now the program makes sense, thanks a lot.

What is that infinite pi-notation?
Can you explain it...
Simply?