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A345940
Factorial of the largest prime factor of n, read modulo n: a(n) = A006530(n)! mod n.
2
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
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
KEYWORD
nonn,look
AUTHOR
Antti Karttunen, Jul 04 2021
STATUS
approved