Voozh

A229264

Primes in A065387 in the order of their appearance.

2, 19, 19, 79, 103, 113, 257, 523, 509, 1151, 1279, 1193, 1579, 2273, 3061, 2389, 2693, 2843, 5003, 4831, 5119, 7411, 5693, 5623, 8623, 6323, 10139, 8933, 18401, 14957, 20411, 20479, 21191, 20123, 29683, 28211, 36833, 55021, 57203, 68743, 48761, 66533, 62423

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1000

EXAMPLE

Third term of A038344 is 9 and sigma(9) + phi(9) = 13 + 6 = 19 is prime.

MAPLE

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

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

MATHEMATICA

Select[Table[DivisorSigma[1, n]+EulerPhi[n], {n, 30000}], PrimeQ] (* Harvey P. Dale, Apr 30 2018 *)

PROG

(PARI) lista(kmax) = {my(f, s); for(k = 1, kmax, f = factor(k); s= sigma(f) + eulerphi(f); if(isprime(s), print1(s, ", "))); } \\ Amiram Eldar, Nov 19 2024

CROSSREFS

Cf. A000005, A000010, A000203, A009087, A023194, A038344, A055813, A062700, A064205, A065387, A115919, A141242, A229265, A229266, A229267, A229268.

Sequence in context: A153653 A065643 A038031 * A132129 A125611 A340922

Adjacent sequences: A229261 A229262 A229263 * A229265 A229266 A229267

KEYWORD

nonn

AUTHOR

Paolo P. Lava, Sep 18 2013

EXTENSIONS

Name corrected by Amiram Eldar, Nov 19 2024

STATUS

approved

URL: https://oeis.org/A229264

⇱ A229264 - OEIS