I entered the obfuscated C contest one year with a program that computed a prime sieve in an incredibly slow and non-intuitive manner. I don't think anyone ever figured out what it did ---- it was so slow and ugly that no one would look at it.
Hilarie
____________________________________________Ah, an obbortunity to refustigate with this Mathematica malpractice:
OddPrimeQ[n_]:= Block[{$RecursionLimit=Infinity},n+1==Odd4[(n-1)/2,0,4]] Odd4[n_,t_,k_]:=If[k==0,KroneckerDelta[0,n], If[t>n,0,Odd4[n-t,0,k-1]+Odd4[n,1/2+t+Sqrt[2*t+1/4],k]]] Absolutely useless hint: OddPrimeQ[n_]:= Block[{$RecursionLimit=Infinity},n^3+1==Odd4[n-1,0,8]] gets the same answers, only more slowly. The only Funster to come close to explaining this was Joshua Zucker, who stopped short of totally cooking it, but correctly indicated the final steps. (Marc LeBrun is disqualified--he helped misbeget it.) --rwg For a modicum of speed: Odd4[n_,t_,k_]:=Odd4[n,t,k]= If[k==0,KroneckerDelta[0,n], If[t>n,0,Odd4[n-t,0,k-1]+Odd4[n,1/2+t+Sqrt[2*t+1/4],k]]] I don't know whether OddPrimeQ[n_]:=Block[{$RecursionLimit=Infinity}, (Odd4[(n-1)/2,0,4]-1)^3==Odd4[n-1,0,8]-1] can give a false positive. It's too slow to test beyond a few thousand. But I see how, with Macsyma, to test its conjecture out to a few million. DAZ> it was a *positive* "No". As opposed to a positive, definite "No". DDyer>I've had waxy paper ... burst into flames while the tamale was still cold. Isn't "cold tamale" an oxymoron?