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 A225890 Composite numbers n such that A179382((n+1)/2)=(n-1)/(2^c) for some c > 0. 1

%I

%S 92673,143713,3579553,4110529,28688897,127017857,141127681,157648097,

%T 162101441

%N Composite numbers n such that A179382((n+1)/2)=(n-1)/(2^c) for some c > 0.

%C 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 143713=137*1049: A179382((143713+1)/2)=4491=(143713-1)/(2^5)

%o (PARI) oddres(n)=n>>valuation(n, 2)

%o cyc(d)=my(k=1, t=1); while((t=oddres(t+d))>1, k++); k

%o 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 Cf. A179382.

%K nonn,more

%O 1,1

%A _Lear Young_ and Peter Košinár, May 20 2013

%E Missing a(3) from _Giovanni Resta_, May 20 2013

%E a(6)-a(9) from _Giovanni Resta_, May 21 2013

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Last modified September 16 15:58 EDT 2021. Contains 347473 sequences. (Running on oeis4.)