This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A225890 #32 May 21 2013 08:08:58 %S A225890 92673,143713,3579553,4110529,28688897,127017857,141127681,157648097, %T A225890 162101441 %N A225890 Composite numbers n such that A179382((n+1)/2)=(n-1)/(2^c) for some c > 0. %C A225890 a(10) > 180*10^6. All terms up to a(9) are of the form 32*k+1 and except a(1) are also semiprimes. The numbers 212999489, 393300097 and 663414881 are also terms. - _Giovanni Resta_, May 21 2013 %e A225890 143713=137*1049: A179382((143713+1)/2)=4491=(143713-1)/(2^5) %o A225890 (PARI) oddres(n)=n>>valuation(n, 2) %o A225890 cyc(d)=my(k=1, t=1); while((t=oddres(t+d))>1, k++); k %o A225890 p=5;forprime(q=7,1e7,forstep(n=p+2, q-2, 2, my(t=(n-1)/cyc(n), c=valuation(t,2)); if(t>>c==1 && c>0, print1(n", ")));p=q) \\ _Charles R Greathouse IV_, May 20 2013 %Y A225890 Cf. A179382. %K A225890 nonn,more %O A225890 1,1 %A A225890 _Lear Young_ and Peter Košinár, May 20 2013 %E A225890 Missing a(3) from _Giovanni Resta_, May 20 2013 %E A225890 a(6)-a(9) from _Giovanni Resta_, May 21 2013