Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #46 Apr 21 2018 17:41:31
%S 315,420,495,525,585,630,660,735,765,780,819,825,840,855,945,975,990,
%T 1020,1035,1050,1071,1092,1140,1170,1260,1275,1287,1320,1380,1425,
%U 1428,1470,1485,1530,1540,1560,1575,1638,1650,1665,1680,1683,1710,1716,1725,1755,1815,1820,1827,1845,1881,1890,1911,1925
%N Nonsquarefree orders of cyclotomic polynomials containing a coefficient with an absolute value greater than one.
%C Numbers in A013590 that are not squarefree.
%o (PARI) is(n)=if (!issquarefree(n), for(k=0, n, if(abs(polcoeff(polcyclo(n), k))>1, return(n))); 0)
%o for(n=1, 10^4, if(is(n), print1(n, ", "))) \\ edited by _Michel Marcus_, Apr 21 2018
%Y Cf. A013590, A013595.
%K nonn
%O 1,1
%A _Derek Orr_, Apr 22 2015