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

92673, 143713, 3579553, 4110529, 28688897, 127017857, 141127681, 157648097, 162101441

Offset: 1

Author

Lear Young and Peter Košinár, May 20 2013

Keywords

• nonn
• more

Comments

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

Examples

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

Crossrefs

Cf. A179382.

Programs

PARI

oddres(n)=n>>valuation(n, 2)
cyc(d)=my(k=1, t=1); while((t=oddres(t+d))>1, k++); k
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

Extensions

Missing a(3) from Giovanni Resta, May 20 2013

a(6)-a(9) from Giovanni Resta, May 21 2013