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 A366074 #10 Feb 16 2025 08:34:06
%S A366074 0,1,1,1,1,2,1,0,1,2,1,2,1,2,2,1,1,2,1,2,2,2,1,1,1,2,0,2,1,3,1,0,2,2,
%T A366074 2,2,1,2,2,1,1,3,1,2,2,2,1,2,1,2,2,2,1,1,2,1,2,2,1,3,1,2,2,0,2,3,1,2,
%U A366074 2,3,1,1,1,2,2,2,2,3,1,2,1,2,1,3,2,2,2
%N A366074 The number of "Fermi-Dirac primes" (A050376) that are unitary divisors of n.
%C A366074 First differs from A293439 at n = 128.
%H A366074 Amiram Eldar, <a href="/A366074/b366074.txt">Table of n, a(n) for n = 1..10000</a>
%H A366074 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/UnitaryDivisor.html">Unitary Divisor</a>.
%F A366074 Additive with a(p^e) = A209229(e).
%F A366074 Sum_{k=1..n} a(k) ~ n * (log(log(n)) + B + C), where B is Mertens's constant (A077761) and C = -P(2) + Sum_{k>=1} (P(2^k) - P(2^k+1)) = -0.13145993422430119364..., where P(s) is the prime zeta function.
%t A366074 f[p_, e_] := If[e == 2^IntegerExponent[e, 2], 1, 0]; a[1] = 0; a[n_] := Plus @@ f @@@ FactorInteger[n]; Array[a, 100]
%o A366074 (PARI) a(n) = vecsum(apply(x -> (x == 1 << valuation(x, 2)), factor(n)[, 2]));
%Y A366074 Cf. A050376, A064547, A077610, A077761, A209229, A366073.
%K A366074 nonn,easy
%O A366074 1,6
%A A366074 _Amiram Eldar_, Sep 28 2023