A368425 The corresponding greatest common divisors to A368424(n).

5, 23, 19, 5, 47, 29, 71, 431, 97, 53, 167, 191, 505, 239, 263, 139, 149, 311, 163, 499, 173, 359, 383, 197, 409, 211, 643, 479, 503, 23, 269, 293, 599, 1201, 317, 647, 19, 719, 743, 379, 389, 839, 863, 887, 461, 11113, 983, 5, 509, 1031, 4297, 557, 1129

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..1000

Example

a(2) = 23 since gcd(A019320(A368424(2)), A019321(A368424(2))) = gcd(2047, 88573) = 23.

Maple

subs(1=NULL, [seq(igcd(numtheory:-cyclotomic(n, 2), numtheory:-cyclotomic(n, 3)), n=1..1000)]); # Robert Israel, Dec 26 2023

Mathematica

Select[GCD[Cyclotomic[Range[600], 2], Cyclotomic[Range[600], 3]], #>1&] (* Stefano Spezia, Dec 26 2023 *)

Prog

(PARI) for(n=1, 1000, m=gcd(polcyclo(n, 2), polcyclo(n, 3)); if(m>1, print1(m, ", ")))

Crossrefs

Cf. A019320, A019321, A191609 (primes dividing some term of this sequence), A368424.

Sequence in context: A177242 A233756 A002582 * A102723 A136146 A289278

Adjacent sequences: A368422 A368423 A368424 * A368426 A368427 A368428

Keyword

nonn,look

Author

Tomohiro Yamada, Dec 24 2023

Status

approved