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A318828
a(n) = n - A063994(n) = n - Product_{primes p dividing n} gcd(p-1, n-1).
6
0, 1, 1, 3, 1, 5, 1, 7, 7, 9, 1, 11, 1, 13, 11, 15, 1, 17, 1, 19, 17, 21, 1, 23, 21, 25, 25, 25, 1, 29, 1, 31, 29, 33, 31, 35, 1, 37, 35, 39, 1, 41, 1, 43, 37, 45, 1, 47, 43, 49, 47, 49, 1, 53, 51, 55, 53, 57, 1, 59, 1, 61, 59, 63, 49, 61, 1, 67, 65, 67, 1, 71, 1, 73, 71, 73, 73, 77, 1, 79, 79, 81, 1, 83, 69, 85, 83, 87, 1, 89, 55
OFFSET
1,4
LINKS
FORMULA
a(n) = n - A063994(n).
PROG
(PARI)
A063994(n) = { my(f=factor(n)[, 1]); prod(i=1, #f, gcd(f[i]-1, n-1)); }; \\ From A063994
A318828(n) = (n-A063994(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 09 2018
STATUS
approved