cp's OEIS Frontend

A229265 Numbers k such that sigma(k) + tau(k) + phi(k) is a prime, where sigma(k) = A000203(k), tau(k) = A000005(k) and phi(k) = A000010(k).

%I A229265 #15 Jul 28 2025 20:19:34
%S A229265 1,8,200,512,968,1458,3200,4232,5618,5832,6962,10368,16928,26912,
%T A229265 36992,40328,53792,61952,84050,101250,110450,140450,147968,220448,
%U A229265 247808,249218,253472,257762,279752,282752,320000,336200,344450,359552,361250,445568,472392,512072
%N A229265 Numbers k such that sigma(k) + tau(k) + phi(k) is a prime, where sigma(k) = A000203(k), tau(k) = A000005(k) and phi(k) = A000010(k).
%e A229265 sigma(200) = 465, tau(200) = 12, phi(200) = 80 and 465 + 12 + 80 = 557 is prime.
%p A229265 with(numtheory); P:=proc(q) local n; for n from 1 to q do
%p A229265 if isprime(sigma(n)+tau(n)+phi(n)) then print(n); fi; od; end: P(10^6);
%Y A229265 Cf. A000005, A000010, A000203, A009087, A023194, A038344, A055813, A062700, A064205, A115919, A141242, A229264, A229266-A229268.
%K A229265 nonn
%O A229265 1,2
%A A229265 _Paolo P. Lava_, Sep 18 2013