A229266 Primes of the form sigma(n) + tau(n) + phi(n), where sigma(n) = A000203(n), tau(n) = A000005(n) and phi(n) = A000010(n).

3, 23, 557, 1289, 2447, 3779, 9209, 10331, 11351, 18367, 14051, 34351, 42953, 67883, 95717, 96587, 134807, 164249, 193057, 310553, 253159, 321397, 383723, 548213, 657311, 499151, 630023, 516251, 732181, 713927, 927013, 932431, 784627, 906473, 855331, 1121987

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Example

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

Maple

with(numtheory); P:=proc(q) local a, n; for n from 1 to q do a:=sigma(n)+tau(n)+phi(n);
if isprime(a) then print(a); fi; od; end: P(10^6);

Mathematica

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

Crossrefs

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

Sequence in context: A134050 A101191 A127900 * A143985 A333739 A119669

Adjacent sequences: A229263 A229264 A229265 * A229267 A229268 A229269

Keyword

nonn

Author

Paolo P. Lava, Sep 18 2013

Status

approved