This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A386557 #14 Aug 03 2025 16:51:31
%S A386557 1,2,10,6,60,42,210,780,420,2730,5460,3570,10920,30030,94710,231420,
%T A386557 510510,190190,1504230,2552550,285285,15120105,1141140,570570,
%U A386557 60480420,78768690,380570190,577642065,514083570
%N A386557 Smallest k for which A384834(k) = n.
%t A386557 f[n_] := DivisorSum[n, 1 &, PowerMod[-#, #, n] == n - # &]; With[{t = Array[f, 10^6]}, TakeWhile[FirstPosition[t, #] & /@ Range[Max[t]] // Flatten, ! MissingQ[#] &]] (* _Amiram Eldar_, Jul 26 2025 *)
%Y A386557 Cf. A386409, A384834.
%K A386557 nonn,more
%O A386557 1,2
%A A386557 _Juri-Stepan Gerasimov_, Jul 25 2025
%E A386557 a(25)-a(29) from _Amiram Eldar_, Jul 26 2025