The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A230799 The number of distinct nonzero coefficients in the n-th cyclotomic polynomial. 2
 2, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 2, 1, 2, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The sum of the coefficients in the n-th cyclotomic polynomial is given by A020500. The first occurrence of 4 in this sequence is a(330). LINKS Colin Barker, Table of n, a(n) for n = 1..1000 EXAMPLE a(12)=2 because the distinct nonzero coefficients of the 12th cyclotomic polynomial, x^4 - x^2 + 1, are 1 and -1. MAPLE A230799 := n -> nops({coeffs(numtheory[cyclotomic](n, z), z)}): seq(A230799(n), n=1..86); # Peter Luschny, Oct 30 2013 MATHEMATICA a[n_] := List @@ Cyclotomic[n, x] /. x -> 1 // Union // Length; Array[a, 100] (* Jean-François Alcover, Jul 08 2019 *) PROG (PARI) a(n) = v=vecsort(Vec(polcyclo(n)), , 8); if(has_zero(v), #v-1, #v) has_zero(v) = for(i=1, #v, if(v[i]==0, return(1))); 0 (PARI) {a(n) = if( n<1, 0, #setminus( Set( Vec( polcyclo(n))), [0]))}; /* Michael Somos, Mar 27 2014 */ CROSSREFS Cf. A020500, A230798. Sequence in context: A321650 A205007 A078470 * A279496 A151683 A133912 Adjacent sequences: A230796 A230797 A230798 * A230800 A230801 A230802 KEYWORD nonn AUTHOR Colin Barker, Oct 30 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 2 21:27 EDT 2024. Contains 374875 sequences. (Running on oeis4.)