A124402 Numbers k such that 3^k mod 2^k < 3^(k-1) mod 2^(k-1).

4, 7, 17, 20, 24, 27, 29, 40, 45, 48, 49, 53, 55, 57, 61, 62, 65, 67, 72, 76, 79, 82, 83, 85, 88, 91, 95, 100, 101, 106, 107, 109, 112, 119, 124, 136, 139, 142, 149, 151, 153, 158, 159, 164, 165, 167, 171, 178, 186, 189, 193, 197, 198, 202, 204, 209, 210, 215, 219

Offset: 1

Author

Robert G. Wilson v, Dec 14 2006

Keywords

• nonn

Comments

Also indices k such that A002380(k) < A002380(k-1).

Examples

			1 == 3^4 (mod 2^4) which is less than 3 == 3^3 (mod 2^3) so 4 is a term.
		

Crossrefs

Cf. A002380.

Programs

Mathematica

pm = 0; lst = {}; Do[pn = PowerMod[3, n, 2^n]; If[pn < pm, AppendTo[lst, n]]; pm = pn, {n, 221}]; lst