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A354189
Numbers k for which phi(A267099(k)) is equal to phi(k), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes, and phi is Euler totient function.
8
1, 2, 4, 8, 15, 16, 30, 32, 35, 39, 60, 64, 70, 78, 91, 120, 128, 140, 156, 182, 187, 225, 240, 256, 280, 312, 364, 374, 450, 480, 512, 551, 560, 624, 728, 748, 851, 900, 960, 1024, 1102, 1120, 1248, 1271, 1365, 1456, 1496, 1702, 1800, 1920, 2048, 2204, 2240, 2279, 2496, 2542, 2730, 2747, 2759, 2805, 2867, 2912, 2992
OFFSET
1,2
COMMENTS
Not a subsequence of A072202. The first term that is included here, but not in that sequence is 69037, as A000010(69037) = A354102(69037) = 62400, although 69037 = 17*31*131. See A354194.
LINKS
FORMULA
{k | A354102(k) == A000010(k)}.
PROG
(PARI)
A354188(n) = (eulerphi(A267099(n)) == eulerphi(n)); \\ Uses the program given in A267099.
isA354189(n) = A354188(n);
CROSSREFS
Positions of zeros in A354101.
Subsequence of A354109.
Cf. A000079, A354192, A354194 (subsequences), A354188 (characteristic function).
Sequence in context: A277166 A078613 A072202 * A275474 A354192 A076351
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 19 2022
STATUS
approved