A106128 - OEIS

%I #18 Oct 13 2022 16:52:00

%S 1,3,6,36,46,78,6915,6916,613375,613378,613404,613406,613414,613438,

%T 613448,613454,613456,613508,613519,613522,613532,613559,613568,

%U 613570,613582,613586,613598,58155528,58155536,58155549,6384425454,6384425520,6384425522,6384425528,6384425638

%N Numbers k such that the k-th semiprime == 3 (mod k).

%C a(48) > 10^12. - _Lucas A. Brown_, Oct 13 2022

%H Lucas A. Brown, <a href="/A106128/b106128.txt">Table of n, a(n) for n = 1..47</a>

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

%e a(3) = 6 is a term because the 6th semiprime is 15 and 15 == 3 (mod 6).

%Y Cf. A001358, A357807.

%K hard,nonn

%O 1,2

%A _Shyam Sunder Gupta_, May 07 2005

%E a(28)-a(30) from _Donovan Johnson_, Oct 29 2008

%E a(1), a(2), and a(31)-a(47) by _Lucas A. Brown_, Oct 19 2020