

A146960


Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) is not coefficient convex.


1



7735, 11305, 13845, 17255, 20615, 21945, 22015, 23919, 25935, 26565, 28595, 31535, 33495, 33915, 35105, 35805, 36465, 39767, 39865, 40755, 41041, 41055, 42315, 42665, 42735, 45885, 46189, 46655, 47355, 47957, 49665, 50505, 51051, 51765
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OFFSET

1,1


COMMENTS

Gallot and Moree say that a cyclotomic polynomial is coefficient convex if the union of the coefficients is a range of consecutive integers. They prove that if n is ternary (the product of three distinct odd primes), then Phi(n,x) is coefficient convex. All numbers in this sequence have more than three odd prime factors.


LINKS



MATHEMATICA

nn = Select[Range[1155, 59999, 2], SquareFreeQ[#] && PrimeNu[#] > 3&];
Reap[For[k = 1, k <= Length[nn], k++, n = nn[[k]]; If[{1} != (CoefficientList[Cyclotomic[n, x], x] // Union // Differences // Union), Print[n]; Sow[n]]]][[2, 1]] (* JeanFrançois Alcover, Nov 11 2018 *)


CROSSREFS

Subsequence of A056911 (odd squarefree numbers).


KEYWORD

nonn


AUTHOR



EXTENSIONS

Definition corrected by T. D. Noe, Nov 16 2008


STATUS

approved



