OFFSET
1,15
COMMENTS
When (as at n=105) coefficients are not equal 1 or -1 then terms in C[n,x] are counted with multiplicity. - This is the comment by the original author. However, the claim contradicts the given formula, as A051664 counts each nonzero coefficient just once, regardless of its value. For the version summing the absolute values of the coefficients (thus "with multiplicity"), see A318886. - Antti Karttunen, Sep 10 2018
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
EXAMPLE
n=21: Cyclotomic[21,x]=1-x+x^3-x^4+x^6-x^8+x^9-x^11+x^12 has 9 terms while largest prime factor of 21 is 7
MATHEMATICA
Array[Length@ Cyclotomic[#, x] - FactorInteger[#][[-1, 1]] &, 105] (* Michael De Vlieger, Sep 10 2018 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, May 03 2002
EXTENSIONS
Data section extended to 105 terms by Antti Karttunen, Sep 10 2018
STATUS
approved