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A226105 Numbers k such that phi(k)+3 divides k+3, excluding numbers of the form 6*p for a prime p. 1
1, 195, 5187, 1141967133868035, 3658018932844533311864835 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Terms having (k+3)/(phi(k)+3) = 2 are shared with A350777. - Max Alekseyev, Oct 26 2023
LINKS
MATHEMATICA
Select[Range[10000000], !PrimeQ[#/6] && IntegerQ[(# + 3)/(EulerPhi[#] + 3)] &]
PROG
(PARI) for(n=1, 10^8, if( (n+3)%(eulerphi(n)+3)==0 && (n%6 || !isprime(n\6)), print(n)));
CROSSREFS
Set difference of A226104 and 6 * A000040.
Sequence in context: A259694 A066232 A284960 * A164130 A084232 A145305
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
Edited and a(4)-a(5) added by Max Alekseyev, Nov 5 2023
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)