A229266 - OEIS

%I #18 Oct 03 2023 17:52:10

%S 3,23,557,1289,2447,3779,9209,10331,11351,18367,14051,34351,42953,

%T 67883,95717,96587,134807,164249,193057,310553,253159,321397,383723,

%U 548213,657311,499151,630023,516251,732181,713927,927013,932431,784627,906473,855331,1121987

%N Primes of the form sigma(n) + tau(n) + phi(n), where sigma(n) = A000203(n), tau(n) = A000005(n) and phi(n) = A000010(n).

%e The third term of A229265 is 200 and sigma(200) +  tau(200) + phi(200) = 465 + 12 + 80 = 557 is prime.

%p with(numtheory); P:=proc(q) local a, n; for n from 1 to q do a:=sigma(n)+tau(n)+phi(n);

%p if isprime(a) then print(a); fi; od; end: P(10^6);

%t Select[Table[DivisorSigma[0,n]+DivisorSigma[1,n]+EulerPhi[n],{n,10^6}],PrimeQ] (* _Harvey P. Dale_, Oct 03 2023 *)

%Y Cf. A000005, A000010, A000203, A009087, A023194, A038344, A055813, A062700, A064205, A115919, A141242, A229264, A229265, A065061, A229268.

%K nonn

%O 1,1

%A _Paolo P. Lava_, Sep 18 2013