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 A383017 #11 Apr 29 2025 16:52:34 %S A383017 2,3,5,7,11,13,17,19,23,29,30,31,36,37,41,42,43,47,53,59,61,64,66,67, %T A383017 70,71,73,78,79,83,89,97,100,101,102,103,105,107,109,110,113,114,127, %U A383017 130,131,137,138,139,149,151,154,157,163,165,167,170,173,174,179 %N A383017 Numbers k such that A382883(k) = -1. %C A383017 See the comments in A382883. %F A383017 A382883 = this sequence union A383016 union A382943. %F A383017 A000040 is a subsequence. %t A383017 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[#] == -1 &] (* _Amiram Eldar_, Apr 29 2025 *) %o A383017 (SageMath) %o A383017 def A383017List(upto): return [n for n in srange(1, upto) if A382883(n) == -1] %Y A383017 Cf. A382883, A382943, A383016, A000040, A325264. %K A383017 nonn %O A383017 1,1 %A A383017 _Peter Luschny_, Apr 12 2025