A039779 Numbers k such that phi(k) is equal to A008473(k).

1, 54, 99, 112, 540, 3344, 4743, 6720, 7644, 8307, 11088, 12852, 15225, 20300, 22320, 83160, 86304, 94944, 129504, 160208, 186992, 200640, 205712, 207264, 266266, 280592, 331731, 364941, 383724, 404550, 441232, 445050, 447876, 449072, 454575, 458052, 497781

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..866 (terms below 10^10)

Example

phi(54) = 18, 54 = 2^1*3^3, (2+1)*(3+3) = 18.

Mathematica

Reap[For[n = 1, n < 500000, n++, If[EulerPhi[n] == Times @@ Plus @@@ FactorInteger[n], Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, May 06 2017 *)

Prog

(PARI) is(k) = {my(f = factor(k)); eulerphi(f) == prod(i = 1, #f~, f[i, 1] + f[i, 2]); } \\ Amiram Eldar, Dec 04 2024

Crossrefs

Cf. A000010, A008473.

Sequence in context: A088986 A259717 A118150 * A044143 A044524 A095962

Adjacent sequences: A039776 A039777 A039778 * A039780 A039781 A039782

Keyword

nonn

Author

Olivier Gérard

Status

approved