A176817 Nonprimes k such that 2^(k-1) == 4^(k-1) (mod k).
1, 4, 8, 16, 28, 32, 64, 112, 128, 256, 341, 448, 496, 512, 561, 645, 1016, 1024, 1105, 1288, 1387, 1729, 1792, 1905, 2044, 2047, 2048, 2416, 2465, 2701, 2821, 3277, 4033, 4096, 4369, 4371, 4672, 4681, 4984, 5461, 6601, 7168, 7936, 7957, 8128, 8192, 8321, 8481, 8911
Offset: 1
Keywords
Programs
-
Mathematica
fQ[n_] := !PrimeQ@ n && PowerMod[2, n - 1, n] == PowerMod[4, n - 1, n]; Select[ Range@ 10000, fQ]
Comments