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A216697
Numbers n such that sigma(n) mod n = 12, n is divisible by 6, but n/6 is not prime.
0
24, 54, 780, 2352, 430272, 184773312
OFFSET
1,1
COMMENTS
Motivated by A076496 comment: if n=6p, p>3 prime, then Mod(sigma(n),n)=12. So this sequence is included in A076496, but not in A084306.
Next term > 10^11. - Donovan Johnson, Sep 27 2012
EXAMPLE
sigma(24) = 60 = 2*24+12, but 24/6=4 is not prime.
PROG
(PARI) isOk(n) = { return ((n % 6 == 0) && (! isprime(n/6)) && (sigma(n) % n == 12)); }
CROSSREFS
Sequence in context: A038635 A003756 A135191 * A332541 A316361 A277108
KEYWORD
nonn
AUTHOR
Michel Marcus, Sep 15 2012
STATUS
approved