A193679 Sequence related to discriminant of cyclotomic polynomials A004124.

1, 2, 3, 4, 5, 12, 7, 16, 27, 80, 11, 144, 13, 448, 2025, 256, 17, 1728, 19, 6400, 35721, 11264, 23, 20736, 3125, 53248, 19683, 200704, 29, 518400, 31, 65536, 7144929, 1114112, 37515625, 2985984, 37, 4980736, 89813529, 40960000, 41, 146313216, 43, 126877696

Offset

1,2

Comments

a(p) = p for primes p.

References

P. Ribenboim, Classical Theory of Algebraic Numbers, Springer, 2001, p. 297, eq.(1).

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Mohammad K. Azarian, On the Hyperfactorial Function, Hypertriangular Function, and the Discriminants of Certain Polynomials, International Journal of Pure and Applied Mathematics, Vol. 36, No. 2, 2007, pp. 251-257. Mathematical Reviews, MR2312537. Zentralblatt MATH, Zbl 1133.11012.

Eric Weisstein's World of Mathematics, Cyclotomic Polynomial

Formula

a(n) = n^phi(n)/abs(discriminant(Phi(n,x))), n>=1, with the cyclotomic polynomials Phi(n,x) and the Euler totient function phi(n)=A000010(n).

a(n) = product(p^(phi(n)/(p-1)),p prime dividing n), n>=2, a(1)=1.

Conjecture: Dirichlet g.f. of log(a(n)): -zeta(s-1)*zeta'(s)/zeta(s)^2, where zeta'(s) is the derivative of zeta(s). This would give a(n) = exp(Sum_{d|n} Lambda(d)*phi(n/d)), with Lambda(n)=log(A014963) and phi(n)=A000010. - Benedict W. J. Irwin, Jul 14 2018

Example

n=6: a(6) = 2^(2/(2-1))*3^(2/(3-1)) = 12.
     Discriminant(Phi(6,x)) = -3 = - (6^phi(6))/a(6).

Maple

with(numtheory): A193679 := n -> n^phi(n)/abs(discrim(cyclotomic (n, x), x)); seq(A193679(i), i=1..49); # Peter Luschny, Aug 20 2011

Mathematica

a[n_] := n^EulerPhi[n]/Abs[Discriminant[Cyclotomic[n, x], x]]; Array[a, 44]
(* Jean-François Alcover, Mar 21 2017 *)

Prog

(PARI) a(n) = n^eulerphi(n)/abs(poldisc(polcyclo(n))); \\ Michel Marcus, Jul 14 2018

Crossrefs

Cf. A004124.

Sequence in context: A327262 A344370 A143482 * A066574 A240304 A325684

Adjacent sequences: A193676 A193677 A193678 * A193680 A193681 A193682

Keyword

nonn

Author

Wolfdieter Lang, Aug 20 2011

Status

approved