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A326145 Numbers n for which n - A007947(n) is equal to gcd(n - A007947(n), sigma(n) - A007947(n) - n). 4
6, 28, 496, 936, 1638, 8128, 33550336 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Numbers n such that either A066503(n) and A326143(n) are both zero or A066503(n) is not zero and divides A326143(n).
Question: Are there any odd terms?
No other terms < 2^31.
LINKS
PROG
(PARI)
A007947(n) = factorback(factorint(n)[, 1]);
isA326145(n) = { my(b=A007947(n), t=n-b, u = (sigma(n)-b)-n); (gcd(t, u)==t); };
\\ Or alternatively as:
isA326145(n) = { my(t=A326143(n), u=A066503(n)); ((!u && !t)||(u && !(t%u))); };
CROSSREFS
Sequence in context: A325025 A325023 A138876 * A174633 A345004 A370789
KEYWORD
nonn,more
AUTHOR
Antti Karttunen, Jun 09 2019
STATUS
approved

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Last modified March 29 04:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)