A070518 Value of n-th cyclotomic polynomial at n.

0, 3, 13, 17, 781, 31, 137257, 4097, 532171, 9091, 28531167061, 20593, 25239592216021, 7027567, 2392743361, 4294967297, 51702516367896047761, 34006393, 109912203092239643840221, 25536159601, 7006306553612521, 25405143539623, 949112181811268728834319677753

Offset: 1

Author

Labos Elemer, May 02 2002

Keywords

• nonn

Comments

a(28341) is divisible by 283411^2. What is the next n such that a(n) is not squarefree? - Jianing Song, Nov 01 2024

Examples

			n=10: 10th cyclotomic polynomial is 1-x+x^2-x^3+x^4; at x=10 it gives a(10)=9091.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..250
• Mathematics Stack Exchange, Is the "cyclotomic diagonalization" always squarefree?
• Eric Weisstein's World of Mathematics, Cyclotomic Polynomial

Crossrefs

Cf. A070519 (indices of prime terms), A088790 (prime indices of prime terms).

Programs

Maple

a:= n-> numtheory[cyclotomic](n$2):
seq(a(n), n=1..25);  # Alois P. Heinz, Jul 05 2024

Mathematica

Table[Cyclotomic[w, w], {w, 1, 35}]

PARI

a(n) = polcyclo(n, n) \\ Michel Marcus, Apr 02 2016