3,2

Every nonnegative integer seems to appear in the sequence, and every integer seems to appear in the sequence of first differences (see link).

Table of n, a(n) for n=3..86.

Enrique Navarrete, Sequences Derived from Residues of 2^n (mod n)

For n=11, 2^8 = 256 == 3 mod 11.

Array[PowerMod[2, # - 3, #] &, 80, 3] (* Robert G. Wilson v, Nov 30 2017 *)

Cf. A015910, A212844, A213859.

Sequence in context: A303118 A037178 A077748 * A152753 A113973 A123330

Adjacent sequences: A294386 A294387 A294388 * A294390 A294391 A294392

nonn

Enrique Navarrete, Oct 29 2017

More terms from Robert G. Wilson v, Nov 30 2017, who remarks that for all 3 <= n < 10^9, a(n) != 7.

approved