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a(n) = n + d(n) - phi(n), where d is the number of divisors function, and phi is the Euler totient function.
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%I #16 Feb 28 2022 07:53:27

%S 1,3,3,5,3,8,3,8,6,10,3,14,3,12,11,13,3,18,3,18,13,16,3,24,8,18,13,22,

%T 3,30,3,22,17,22,15,33,3,24,19,32,3,38,3,30,27,28,3,42,10,36,23,34,3,

%U 44,19,40,25,34,3,56,3,36,33,39,21,54,3,42,29,54,3,60,3,42,41,46,21,62,3,58,32,46,3,72,25,48

%N a(n) = n + d(n) - phi(n), where d is the number of divisors function, and phi is the Euler totient function.

%H Antti Karttunen, <a href="/A351561/b351561.txt">Table of n, a(n) for n = 1..20000</a>

%F a(n) = A000005(n) + A051953(n) = n - A063070(n) = n + A000005(n) - A000010(n).

%t Array[# + DivisorSigma[0, #] - EulerPhi[#] &, 86] (* _Michael De Vlieger_, Feb 21 2022 *)

%o (PARI) A351561(n) = (n+numdiv(n)-eulerphi(n));

%Y Cf. A000005, A000010, A020488 (fixed points), A051953, A063070.

%Y Cf. also A055517.

%K nonn

%O 1,2

%A _Antti Karttunen_, Feb 21 2022