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 A382943 #12 Apr 29 2025 16:53:02
%S A382943 12,16,18,20,24,28,40,44,45,48,50,52,54,56,60,63,68,72,75,76,80,81,84,
%T A382943 88,90,92,96,98,99,104,108,112,116,117,120,124,126,132,135,136,140,
%U A382943 144,147,148,150,152,153,156,160,162,164,168,171,172,175,176,180,184,188,189
%N A382943 Numbers k such that A382883(k) = 0.
%C A382943 See the comments in A382883.
%F A382943 a = {n >= 2 | 0 = Sum_{k=2..n} A382881(n, k)}.
%F A382943 A382883 = a union A383016 union A383017.
%F A382943 Conjecture: A059404 is a subsequence.
%t A382943 V[n_, e_] := If[e == 1, 1, IntegerExponent[n, e]]; f[n_] := f[n] = -DivisorSum[n, V[n, #] * f[#] &, # < n &]; f[1] = 1; Select[Range[200], f[#] == 0 &] (* _Amiram Eldar_, Apr 29 2025 *)
%o A382943 (SageMath)
%o A382943 def A382943List(upto): return [n for n in srange(1, upto) if A382883(n) == 0]
%o A382943 # Or:
%o A382943 def isA382943(n): return n > 1 and 0 == sum(A382881(n, k) for k in srange(2, n + 1))
%Y A382943 Cf. A382881, A382883, A383016, A383017, A059404, A217261.
%K A382943 nonn
%O A382943 1,1
%A A382943 _Peter Luschny_, Apr 12 2025