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URL: https://oeis.org/A162281

⇱ A162281 - OEIS

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A162281
Values of sigma_0(n) for n in A162279.
2
4, 4, 4, 4, 4, 8, 4, 8, 4, 4, 4, 4, 8, 4, 8, 4, 4, 8, 4, 4, 8, 12, 4, 8, 4, 8, 4, 4, 4, 8, 6, 4, 4, 8, 4, 8, 12, 4, 4, 4, 8, 4, 4, 4, 4, 8, 4, 8, 12, 4, 4, 8, 16, 4, 8, 12, 4, 8, 4, 6, 4, 4, 12, 4, 8, 4, 4, 8, 4, 12, 4, 8, 4, 8, 12, 4, 4, 8, 6, 4, 8, 16, 12, 4, 4, 4, 4, 8, 4, 12, 4, 8, 4, 4, 8, 4, 8, 12, 4, 8
OFFSET
1,1
COMMENTS
No primes can appear in this sequence; to have sigma_0(n) = p, a prime, we must have n = q^{p-1} for some prime q, and each such n for fixed p will have a distinct value for sigma(n).
Conjecture: every composite number appears in this sequence. - Max Alekseyev
Up to sigma(n) = 500000, the only odd value is 9, for 106276 = 326^2 and 165649 = 407^2; these have sigma(n) = 187131.
FORMULA
a(n) = A000005(A162279(n)) = A000005(A162280(n)).
CROSSREFS
Sequence in context: A085142 A064053 A108893 * A262690 A048760 A287392
KEYWORD
nonn
AUTHOR
STATUS
approved