A385499 a(n) is the smallest integer k such that A385392(k) = n.
1, 2, 6, 42, 70, 870, 44070, 547470, 15410670, 168638470
Offset: 1
Programs
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Mathematica
s[n_] := DivisorSum[n, 1 &, PowerMod[#, #, n] == n - # &]; With[{v = Array[s, 45000]}, TakeWhile[Flatten[FirstPosition[v, #] & /@ Range[Max[v]]], NumberQ]] (* Amiram Eldar, Jul 03 2025 *)
Extensions
a(8)-a(10) from Amiram Eldar, Jul 03 2025