A294389 a(n) = 2^(n-3) mod n, for n >= 3.

1, 2, 4, 2, 2, 0, 1, 8, 3, 8, 10, 4, 1, 0, 13, 8, 5, 12, 1, 6, 6, 8, 4, 20, 10, 16, 22, 8, 8, 0, 1, 26, 11, 8, 28, 10, 1, 32, 31, 8, 11, 24, 19, 12, 12, 32, 16, 28, 1, 28, 40, 44, 26, 32, 1, 44, 15, 32, 46, 16, 1, 0, 4, 8, 17, 36, 1, 58, 18, 8, 55, 56, 46, 40, 60, 8, 20, 32, 10, 62, 21, 8, 4, 22

Offset: 3

Author

Enrique Navarrete, Oct 29 2017

Keywords

• nonn

Comments

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

For all 3 <= n < 10^9, a(n) != 7. - Robert G. Wilson v, Nov 30 2017

Links

• G. C. Greubel, Table of n, a(n) for n = 3..10000
• Enrique Navarrete, Sequences Derived from Residues of 2^n (mod n)

Crossrefs

Cf. A015910, A212844, A213859.

Programs

Magma

[Modexp(2,(n-3),n): n in [3..100]]; // G. C. Greubel, Jan 11 2023

Mathematica

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

SageMath

[power_mod(2,(n-3),n) for n in range(3,101)] # G. C. Greubel, Jan 11 2023

Extensions

More terms from Robert G. Wilson v, Nov 30 2017