%I #33 Oct 11 2019 16:54:02

%S 9356,52412,110442,160834,220884,266866,289230,321668,420790,441768,

%T 533732,556818,578460,643336,731530,841580,883536,1067464,1113636,

%U 1156920,1286672,1446150,1463060,1683160,1767072,2103950,2134928,2227272,2313840,2545888,2573344,2892300

%N Numbers n such that sigma(n) = sigma(n - phi(n)), where sigma(n) is the sum of divisors of n and phi(n) is the Euler totient function of n.

%H Amiram Eldar, <a href="/A228519/b228519.txt">Table of n, a(n) for n = 1..1000</a>

%F sigma(9356- phi(9356)) = sigma(9356 - 4676) = 16380 = sigma(9356).

%p with(numtheory); P:=proc(q) local n; for n from 1 to q do

%p if sigma(n)=sigma(n-phi(n)) then print(n); fi; od; end: P(10^9);

%t Select[Range[10^6], DivisorSigma[1, #] == DivisorSigma[1, # - EulerPhi@ #] &] (* _Michael De Vlieger_, Jun 21 2016 *)

%Y Cf. A000010, A000203, A051953, A067880.

%K nonn,easy

%O 1,1

%A _Paolo P. Lava_, Jun 21 2016