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Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 5.
1

%I #19 Aug 07 2018 03:55:23

%S 1785,2145,2717,2805,3135,3570,3705,3795,3885,3927,4290,4641,4785,

%T 4845,5005,5115,5187,5291,5313,5355,5434,5610,5655,6270,6279,6435,

%U 6545,6699,6765,6783,7035,7095,7140,7215,7293,7315,7410,7455,7590,7735,7770,7854

%N Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 5.

%C n is in the sequence if and only if A007947(n) is in the sequence. - _Robert Israel_, Aug 06 2018

%H Robert Israel, <a href="/A013593/b013593.txt">Table of n, a(n) for n = 1..2000</a>

%p isA013593 := proc(n)

%p numtheory[cyclotomic](n,x) ;

%p {coeffs(%,x)} ;

%p map(abs,%) ;

%p if % minus {1,2,3,4} = {} then

%p false;

%p else

%p true;

%p end if;

%p end proc:

%p for n from 1 do

%p if isA013593(n) then

%p print(n);

%p end if;

%p end do: # _R. J. Mathar_, Nov 28 2016

%t S[ n_ ] := For[ j=1; t=0, j<n, j++, t=Cases[ CoefficientList[ Cyclotomic[ j, x ], x ], k_ /; Abs[ k ]>4 ]; If[ Length[ t ]!=0, Print[ j ] ] ]; S[ 4845 ]

%t Select[Range[8000],Max[Abs[CoefficientList[Cyclotomic[#,x],x]]]>4&] (* _Harvey P. Dale_, Feb 27 2015 *)

%o (PARI) isok(n) = #select(x->abs(x) >= 5, Vec(polcyclo(n))) > 0; \\ _Michel Marcus_, Aug 07 2018

%Y Cf. A007947.

%K nonn

%O 1,1

%A Peter T. Wang (peterw(AT)cco.caltech.edu)

%E More terms from _Don Reble_, Dec 09 2001

%E Definition clarified by _Harvey P. Dale_, Feb 27 2015