Numbers k such that p=6k+1 is prime and cos(2*Pi/p) is an algebraic number of a 3-smooth degree, but not 2-smooth.

A125867

Numbers k such that p=6k+1 is prime and cos(2*Pi/p) is an algebraic number of a 3-smooth degree, but not 2-smooth.

Terms

    a(0) =1a(1) =2a(2) =3a(3) =6a(4) =12a(5) =16a(6) =18a(7) =27a(8) =32a(9) =72a(10) =81a(11) =96a(12) =128a(13) =192a(14) =216a(15) =243a(16) =432a(17) =486a(18) =576a(19) =648a(20) =1728a(21) =2048a(22) =2916a(23) =3072a(24) =6561a(25) =8748a(26) =23328a(27) =24576a(28) =34992a(29) =55296

External references