cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A013594 Smallest order of cyclotomic polynomial containing n or -n as a coefficient.

Original entry on oeis.org

0, 105, 385, 1365, 1785, 2805, 3135, 6545, 6545, 10465, 10465, 10465, 10465, 10465, 11305, 11305, 11305, 11305, 11305, 11305, 11305, 15015, 11305, 17255, 17255, 20615, 20615, 26565, 26565, 26565, 26565, 26565, 26565, 26565, 26565, 26565
Offset: 1

Views

Author

Keywords

Comments

This sequence is infinite - see the Lang reference.
An alternative version would start with 1 rather than 0.

Examples

			a(2)=105 because cyclotomic(105) contains "-2" as coefficient, but for n < 105 cyclotomic(n) does not contain 2 or -2.
x^105 - 1 = ( - 1 + x)(1 + x + x^2)(1 + x + x^2 + x^3 + x^4)(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)(1 - x + x^3 - x^4 + x^5 - x^7 + x^8)(1 - x + x^3 - x^4 + x^6 - x^8 + x^9 - x^11 + x^12)(1 - x + x^5 - x^6 + x^7 - x^8 + x^10 - x^11 + x^12 - x^13 + x^14 - x^16 + x^17 - x^18 + x^19 - x^23 + x^24)(1 + x + x^2 - x^5 - x^6 - 2x^7 - x^8 - x^9 + x^12 + x^13 + x^14 + x^15 + x^16 + x^17 - x^20 - x^22 - x^24 - x^26 - x^28 + x^31 + x^32 + x^33 + x^34 + x^35 + x^36 - x^39 - x^40 - 2x^41 - x^42 - x^43 + x^46 + x^47 + x^48)
		

References

  • Bateman, C. Pomerance and R. C. Vaughan, Colloq. Math. Soc. Janos Bolyai, 34 (1984), 171-202.
  • S. Lang, Algebra: 3rd edition, Addison-Wesley, 1993, p. 281.
  • Maier, Prog. Math. 85 (Birkhaueser), 1990, 349-366.
  • Maier, Prog. Math. 139 (Birkhaueser) 1996, 633-638.

Crossrefs

Programs

  • Mathematica
    Table[Position[Table[Max[Abs[Flatten[CoefficientList[Transpose[FactorList[x^i - 1]][[1]], x]]]], {i, 1, 10000}], j][[1]], {j, 1, 10}] (* Ian Miller, Feb 25 2008 *)
  • PARI
    nm=6545; m=0; forstep(n=1, nm, 2, if(issquarefree(n), p=polcyclo(n); o=poldegree(p); for(k=0, o, a=abs(polcoeff(p, k)); if(a>m, m=a; print([m, n, factor(n)])))))

Extensions

More terms from Eric W. Weisstein
Further terms from T. D. Noe, Oct 29 2007

A013590 Numbers k such that Phi(k,x) is a cyclotomic polynomial containing a coefficient with an absolute value greater than one.

Original entry on oeis.org

105, 165, 195, 210, 255, 273, 285, 315, 330, 345, 357, 385, 390, 420, 429, 455, 495, 510, 525, 546, 555, 561, 570, 585, 595, 609, 615, 627, 630, 645, 660, 665, 690, 705, 714, 715, 735, 759, 765, 770, 777, 780, 795, 805, 819, 825, 840, 855
Offset: 1

Views

Author

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

Keywords

Comments

Previous name was: Orders of cyclotomic polynomials containing a coefficient with an absolute value greater than one.
First occurrence of A137979(n)=k is given in A013594.
From David A. Corneth, Apr 21 2018: (Start)
Terms are composite.
If k is a term of the sequence then so is k * m for m > 0.
Let a primitive term p of this sequence be a term of which no divisor is in the sequence. Then p is an odd squarefree number. (End)

Crossrefs

Flat cyclotomic polynomial: A117223 (order 3), A117318 (order 4).

Programs

  • Maple
    isA013590 := proc(n)
        numtheory[cyclotomic](n,x) ;
        {coeffs(%,x)} ;
        map(abs,%) ;
        if % minus {1}  = {} then
            false;
        else
            true;
        end if;
    end proc:
    for n from 1 do
        if isA013590(n) then
            print(n);
        end if;
    end do: # R. J. Mathar, Nov 28 2016
  • Mathematica
    S[ n_ ] := For[ j=1; t=0, j1 ]; If[ Length[ t ]!=0, Print[ j ] ] ]; S[ 856 ]
    f[n_] := Max@ Abs@ CoefficientList[ Cyclotomic[n, x], x]; Select[ Range@ 1000, f@# > 1 &] (* Robert G. Wilson v *)
    Select[Range[900],Max[Abs[CoefficientList[Cyclotomic[#,x],x]]]>1&] (* Harvey P. Dale, Mar 13 2013 *)
  • PARI
    is(n)=for(k=0,n,if(abs(polcoeff(polcyclo(n),k))>1,return(n)));0
    for(n=1,1000,if(is(n),print1(n,", "))) \\ Derek Orr, Apr 22 2015

Extensions

Definition clarified by Harvey P. Dale, Mar 13 2013
New name from Michel Marcus, Apr 29 2018

A160338 Height (maximum absolute value of coefficients) of the n-th cyclotomic polynomial.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2
Offset: 1

Views

Author

Max Alekseyev, May 13 2009

Keywords

Comments

Different from A137979: first time these sequence disagree is at n=14235 with a(14235)=2 and A137979(14235)=3.

Examples

			a(4) = 1 because the 4th cyclotomic polynomial x^2 + 1 has height 1.
		

Crossrefs

Cf. A160339 (records), A160340 (indices of records), A160341.

Programs

  • Mathematica
    Table[Max@Abs@CoefficientList[Cyclotomic[n,x],x],{n,1,105}] (* from Jean-François Alcover, Apr 02 2011 *)
  • PARI
    a(n) = vecmax(abs(Vec(polcyclo(n))))
Showing 1-3 of 3 results.