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 A374463 #12 Jul 12 2024 14:23:41
%S A374463 1,3,5,15,189,945,2125,6375,9261,42550,46305,127650,401625,936100,
%T A374463 1191400,2808300,3574200,8041950,19679625,22469750,58378600,58506250,
%U A374463 67409250,175135800,175518750,176922900,394055550,494334500
%N A374463 Numbers k such that the odd parts of sigma(k) and A064989(k) are equal, where A064989 shifts the prime factorization one step towards lower primes, and sigma is the sum of divisors function.
%C A374463 Odd terms after 1 form a subsequence of A347391.
%C A374463 If x and y are included, and they are coprime (gcd(x,y) = 1), then x*y is also included.
%F A374463 {k | A000265(sigma(k)) = A000265(A064989(k))}.
%e A374463 945 = 3^3 * 5 * 7 is included as A064989(945) = 2^3 * 3 * 5 = 120, and sigma(945) = 1920 = 2^7 * 3 * 5, with A000265(120) = A000265(1920) = 15.
%o A374463 (PARI) isA374463(n) = (A000265(sigma(n)==A000265(A064989(n))));
%Y A374463 Cf. A000203, A000265, A064989, A161942, A347391, A374464.
%K A374463 nonn,more
%O A374463 1,2
%A A374463 _Antti Karttunen_, Jul 11 2024