A066909 (product of primes < n that do not divide n) (mod n).

0, 1, 2, 3, 1, 5, 2, 1, 7, 1, 1, 1, 9, 3, 7, 7, 8, 17, 18, 9, 16, 15, 15, 1, 24, 1, 26, 13, 17, 1, 19, 9, 14, 23, 3, 23, 11, 31, 19, 1, 6, 37, 26, 21, 7, 45, 35, 35, 25, 41, 2, 17, 27, 1, 31, 43, 50, 41, 15, 49, 55, 9, 10, 51, 28, 37, 30, 13, 26, 47, 24, 13, 28, 27, 73, 73, 76, 43, 4

Offset

1,3

Links

John Tyler Rascoe, Table of n, a(n) for n = 1..10000

Formula

a(n) = A066838(n) modulo n. - Michel Marcus, May 20 2014

a(prime(n)) = A062347(n-1). - Michel Marcus, May 20 2014

Example

a(8) = (3 * 5 * 7) (mod 8) = 1 because 3, 5 and 7 are the primes < 8 that do not divide 8.

Prog

(PARI) a(n) = prod(i=1, n-1, if (isprime(i) && (n%i) , i, 1)) % n; \\ Michel Marcus, May 20 2014

Crossrefs

Cf. A062347, A066838.

Sequence in context: A173239 A366154 A214055 * A095195 A372640 A229961

Adjacent sequences: A066906 A066907 A066908 * A066910 A066911 A066912

Keyword

nonn,easy,changed

Author

Leroy Quet, Jan 22 2002

Status

approved