A069639 Smallest composite k such that phi(k) > k*(1-1/n^2).
4, 25, 121, 289, 841, 1369, 2809, 4489, 6889, 10201, 16129, 22201, 29929, 38809, 51529, 66049, 85849, 109561, 134689, 160801, 196249, 237169, 292681, 332929, 398161, 458329, 537289, 619369, 727609, 822649, 935089, 1062961, 1190281
Offset: 1
Programs
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Mathematica
a[n_] := NextPrime[n^2]^2; Array[a, 40] (* Amiram Eldar, May 08 2025 *)
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PARI
a(n) = nextprime(n^2)^2; \\ Amiram Eldar, May 08 2025
Formula
a(n) = nextprime(n^2)^2 = A007918(n^2)^2.
a(n) = A007491(n)^2. - Amiram Eldar, May 08 2025