const PRIME_LIMIT=1_000_000;
var [const] BI=Import("zklBigNum");  // libGMP
var [const] primeBitMap=Data(PRIME_LIMIT).fill(0x30);   // one big string
p:= BI(1);
while(p.nextPrime()<=PRIME_LIMIT){ primeBitMap[p]="1" } // bitmap of primes

fcn primeWindows(m,deltas){ // eg (6,4,2)
   n,r := 0,List();
   ds:=deltas.len().pump(List,'wrap(n){ deltas[0,n+1].sum(0) });  // (6,10,12)
   sp:=Data(Void,"1" + "0"*deltas.sum(0));
   foreach n in (ds){ sp[n]="1" } // "1000001000101"
   while(n=primeBitMap.find(sp,n+1)){ r.append(n) }  //  (31, 61, 271,...)
   r.apply('wrap(n){ T(n).extend(ds.apply('+(n))) }) //( (31,37,41,43), (61,67,71,73), (271,277,281,283) ...)
}