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 A363896 #51 Aug 07 2023 14:54:10
%S A363896 9,15,16,42
%N A363896 Numbers k such that the sum of primes dividing k (with repetition) is equal to Euler's totient function of k.
%C A363896 No more terms less than 1.6*10^7.
%F A363896 {k : A001414(k) = A000010(k)}.
%t A363896 Select[Range[2, 1000], EulerPhi[#] == Plus @@ Times @@@ FactorInteger[#] &] (* _Amiram Eldar_, Jun 27 2023 *)
%o A363896 (Python)
%o A363896 from sympy import factorint,totient
%o A363896 A001414 = lambda k: sum(p*e for p, e in factorint(k).items())
%o A363896 def g():
%o A363896 k = 2
%o A363896 while True:
%o A363896 if A001414(k) == totient(k): yield(k)
%o A363896 k += 1
%o A363896 for a_n in g():
%o A363896 print(a_n)
%o A363896 (PARI) is(k) = my(f=factor(k)); f[, 1]~*f[, 2] == eulerphi(f); \\ _Amiram Eldar_, Jun 27 2023
%Y A363896 Subsequence of A257048.
%Y A363896 Other sequences requiring a specific relationship between A000010(k) and A001414(k): A173327, A237798, A280936.
%K A363896 nonn,more
%O A363896 1,1
%A A363896 _Darío Clavijo_, Jun 26 2023