A106126 - OEIS

%I #30 Oct 13 2022 12:48:07

%S 1,27,28,35,40,44,47,55,56,72,613400,613401,613457,613482,613530,

%T 613538,613544,613550,613554,613556,613560,613614,58155520,58155521,

%U 58155533,58155537,58155540,58155543,58155545,58155571,6384425460,6384425506,6384425524

%N Numbers k such that k-th semiprime == 1 (mod k).

%C a(45) > 10^12. - _Lucas A. Brown_, Oct 17 2020

%H Lucas A. Brown, <a href="/A106126/b106126.txt">Table of n, a(n) for n = 1..44</a>

%H Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/semiprimemods.py">semiprimemods.py</a>

%e 27 is a term because the 27th semiprime (i.e., 82) == 1 (mod 27).

%Y Cf. A001358, A357781.

%K hard,nonn

%O 1,2

%A _Shyam Sunder Gupta_, May 07 2005

%E a(23)-a(30) from _Donovan Johnson_, Oct 29 2008

%E a(1) and a(31)-a(33) from _Lucas A. Brown_, Oct 17 2020