A345940 Factorial of the largest prime factor of n, read modulo n: a(n) = A006530(n)! mod n.

0, 0, 0, 2, 0, 0, 0, 2, 6, 0, 0, 6, 0, 0, 0, 2, 0, 6, 0, 0, 0, 0, 0, 6, 20, 0, 6, 0, 0, 0, 0, 2, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 30, 0, 0, 6, 42, 20, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 45, 0, 0, 0, 0, 40, 6, 0, 0, 0, 0, 0, 0, 0, 0, 30, 0, 0, 0, 0, 0, 6, 0, 42, 0, 20

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to factorial numbers

Formula

a(n) = A000142(A006530(n)) modulo n.

Mathematica

Table[Mod[First@Last@FactorInteger[n]!, n], {n, 100}] (* Giorgos Kalogeropoulos, Jul 04 2021 *)

Prog

(PARI)
A006530(n) = if(1==n, n, my(f=factor(n)); f[#f~, 1]);
A345940(n) = ((A006530(n)!)%n);

Crossrefs

Cf. A000142, A006530, A057109 (positions of nonzero terms), A345951.

Sequence in context: A153587 A320437 A059286 * A076998 A173956 A306078

Adjacent sequences: A345937 A345938 A345939 * A345941 A345942 A345943

Keyword

nonn,look

Author

Antti Karttunen, Jul 04 2021

Status

approved