A357125 Positive integers n such that 2^(n-3) == -1 (mod n).

1, 5, 4553, 46777, 82505, 4290773, 4492205, 4976429, 21537833, 21549349, 51127261, 56786089, 60296573, 80837773, 87761789, 94424465, 138644873, 168865001, 221395541, 255881453, 297460453, 305198249, 360306365, 562654205, 635374253, 673867253, 808333573, 1164757553, 1210317349

Offset

1,2

Comments

Also, odd integers n dividing 2^n + 8.

Some large terms: 5603900696716667005, 446661376165868432471569407934747098747181600670953926245, 1533278864164902082788937853692280620552397221686019535813.

Links

Max Alekseyev, Table of n, a(n) for n = 1..781 (all terms below 10^15)

Mathematica

Select[Range[2155*10^4], PowerMod[2, #-3, #]==#-1&]//Quiet (* The program generates the first 10 terms of the sequence. *) (* Harvey P. Dale, Feb 08 2025 *)

Crossrefs

The odd terms of A245319.

Cf. A006521, A115976, A276967, A251603.

Sequence in context: A159397 A024074 A276238 * A086896 A177503 A072021

Adjacent sequences: A357122 A357123 A357124 * A357126 A357127 A357128

Keyword

nonn

Author

Max Alekseyev, Sep 13 2022

Status

approved