A297000 Numbers k such that A296992(k) = 1.

5, 7, 10, 14, 15, 20, 25, 28, 30, 35, 45, 49, 50, 56, 60, 63, 70, 75, 80, 88, 90, 91, 92, 98, 100, 105, 112, 115, 125, 126, 140, 147, 150, 160, 161, 175, 180, 182, 196, 200, 207, 210, 224, 225, 230, 240, 245, 250, 252, 264, 273, 276, 294, 300, 315, 320, 322, 343

Offset: 1

Author

Seiichi Manyama and Robert G. Wilson v, Dec 23 2017

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..2000
• Eric Weisstein's World of Mathematics, Tau Function.

Crossrefs

Cf. A000594, A063938, A296992, A297001.

Programs

Mathematica

1 + Position[Table[-1 + SelectFirst[Range[0, 5], ! Divisible[RamanujanTau@ n, n^#] &], {n, 2, 350}], 1][[All, 1]] (* Michael De Vlieger, Dec 23 2017 *)

PARI

isok(k) = if(k == 1, 0, valuation(ramanujantau(k), k) == 1); \\ Amiram Eldar, Jan 09 2025