OFFSET
1,1
REFERENCES
Jean-Marie De Koninck, Those Fascinating Numbers, American Mathematical Society, 2009, page 106, entry 823.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
823 is in the sequence since phi(823) = 822, phi(824) = 408, phi(825) = 400, phi(826) = 348, and 822 > 408 > 400 > 348.
MATHEMATICA
aQ[n_] := AllTrue[Differences @ EulerPhi[n + Range[0, 3]], # < 0 &]; Select[Range[23000], aQ] (* Amiram Eldar, Oct 20 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Kritsada Moomuang, Oct 20 2019
STATUS
approved