A069165 a(n) are the integers corresponding to A069164(n).

1, 3, 33, 55, 75, 77, 121, 125, 121, 143, 175, 187, 275, 209, 274, 275, 253, 325, 319, 341, 425, 407, 475, 588, 451, 473, 575, 517, 583, 725, 649, 1233, 671, 775, 737, 781, 803, 925, 869, 1025, 913, 1075, 979, 1175, 1067, 1111, 1133, 1325, 1177, 2055, 1199

Offset: 1

Author

Benoit Cloitre, Apr 09 2002

Keywords

• easy
• nonn

Comments

The previous name was "Integers of the form k * Sum_{d|k} 1/tau(d)", but this did not take into account the occurrence of multiple terms and the non-ascending order.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A069164, A265391, A265392.

Programs

Mathematica

Select[Table[n * DivisorSum[n, 1/DivisorSigma[0, #] &], {n, 1, 500}], IntegerQ] (* Amiram Eldar, Apr 29 2025 *)

Formula

a(n) = f(A069164(n)), where f(n) = n*A265391(n)/A265392(n). - Amiram Eldar, Apr 29 2025

Extensions

Name corrected by Hugo Pfoertner, Jul 07 2024