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%I #25 Dec 20 2014 03:29:56
%S 1,3,5,15,17,51,85,255,257,771,1285,3855,4369,13107,21845,65535,65537,
%T 196611,327685,983055,1114129,3342387,5570645,16711935,16843009,
%U 50529027,84215045,252645135,286331153,858993459,1431655765,4294967295
%N Divisors of 2^32 - 1 (for a(1) to a(31), the 31 regular polygons with an odd number of sides constructible with ruler and compass).
%C The 32 divisors of the product of the 5 known Fermat primes.
%C The only known odd numbers whose totient is a power of 2. - _Labos Elemer_, Dec 06 2000
%C Equals first 32 members of A001317. Also, equals first 32 members of A053576. - _Omar E. Pol_, Dec 10 2008
%C Omitting the first term a(0)=1 gives A045544 (the number of sides of constructible odd-sided regular polygons.)
%D J. H. Conway and R. K. Guy, The Book of Numbers, Copernicus Press, New York, 1996; see p. 140.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RegularPolygon.html">Regular Polygon</a>, <a href="http://mathworld.wolfram.com/SierpinskiSieve.html">Sierpiński Sieve</a>, <a href="http://mathworld.wolfram.com/ConstructiblePolygon.html">Constructible Polygon</a>
%H OEIS Wiki, <a href="/wiki/Constructible_odd-sided_polygons">Constructible odd-sided polygons</a>
%H OEIS Wiki, <a href="/wiki/Sierpinski's_triangle">Sierpinski's triangle</a>
%H <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a>
%t Divisors[2^32-1]
%o (PARI) divisors(1<<32-1)
%Y Essentially same as A045544.
%Y Cf. A000010, A000215, A001317, A003401, A003527, A004169, A004729, A019434, A045544, A047999, A053576, A054432.
%K nonn,fini,full,easy
%O 0,2
%A _N. J. A. Sloane_
%E Edited by _Daniel Forgues_, Jun 17 2011