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A333408 Numbers k such that s(k) = s(k+1), where s(k) is the unitary analog of the alternating sum-of-divisors function (A307037).

%I A333408 #8 Mar 20 2020 09:08:28
%S A333408 1,11,71,155,194,204,1119,1420,1628,3705,5186,14363,19788,20467,25180,
%T A333408 25545,25843,28251,30804,42811,60204,63180,71791,73260,83600,87219,
%U A333408 87308,91539,97432,99208,100456,100471,119315,122616,132308,135340,135864,164691,166624
%N A333408 Numbers k such that s(k) = s(k+1), where s(k) is the unitary analog of the alternating sum-of-divisors function (A307037).
%H A333408 Amiram Eldar, <a href="/A333408/b333408.txt">Table of n, a(n) for n = 1..1000</a>
%e A333408 1 is a term since s(1) = s(2) = 1;
%e A333408 11 is a term since s(11) = s(12) = 10;
%t A333408 f[p_, e_] := p^e + (-1)^e; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; seq = {}; s1 = 1;  Do[s2 = s[n]; If[s1 == s2, AppendTo[seq, n - 1]]; s1 = s2, {n, 2, 10^5}]; seq
%Y A333408 The unitary version of A206368.
%Y A333408 Cf. A206369, A307037.
%K A333408 nonn
%O A333408 1,2
%A A333408 _Amiram Eldar_, Mar 19 2020