A226104 Numbers n such that phi(n)+3 divides n+3.

1, 30, 42, 66, 78, 102, 114, 138, 174, 186, 195, 222, 246, 258, 282, 318, 354, 366, 402, 426, 438, 474, 498, 534, 582, 606, 618, 642, 654, 678, 762, 786, 822, 834, 894, 906, 942, 978, 1002, 1038, 1074, 1086, 1146, 1158, 1182, 1194, 1266, 1338, 1362, 1374, 1398

Offset: 1

Author

José María Grau Ribas, May 26 2013

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000010 (Euler's totient function).

Cf. A207574 (numbers n such that phi(n)+2 divides n+2).

Cf. A202855 (numbers n such that phi(n)-1 divides n).

Cf. A203966 (numbers n such that phi(n) divides n+1).

Programs

Mathematica

Select[Range[2000], IntegerQ[(# + 3)/(EulerPhi[#] + 3)] &]

PARI

is(n)=(n+3)%(eulerphi(n)+3)==0 \\ Charles R Greathouse IV, Nov 13 2013

Python

from sympy import totient as phi
def ok(n): return (n+3) % (phi(n)+3) == 0
print([m for m in range(1, 1400) if ok(m)]) # Michael S. Branicky, Jan 30 2021