Sieve of Eratostenes:

[code]
+js var buffer = ""; function dump() { return buffer += arguments[0]; }; var n=659,i=2,m=Math.sqrt(n),c = []; while (i <= m) { if (!c[i]) { var s=2; while(s <= n/i) { c[i*s]=1; s++; } } i++; } i=2; while (i <= n) { if (!c[i]) dump(i + " "); i++; }; dump("");
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Euclid's Method:

[code]
+js var buffer = ""; function dump() { return buffer += arguments[0]; }; var e=600851475143, f=e, i=2, s=Math.sqrt(f); while (i < s) { if (e % i == 0) { dump(i + " "); e /= i; if (e == 1) { i=s; } } i++; } dump("");
[/code]

Fibonnaci Sequence:

[code]
+js var buffer = "1 "; function dump() { return buffer += arguments[0]; }; var n=10, f=0, g=1, v, i = 1; while (i < n) { v = f + g; f = g; g = v; i++; dump(v + " "); }; dump("");
[/code]