This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A117921 #14 Feb 16 2025 08:33:00
%S A117921 3373,29789,133432829,8577357821,281462092005373
%N A117921 Primes of the form (2^k - 1)^3 - 2.
%C A117921 Exponent-3 analog of what for exponent 2 is A091516 Carol primes (2^n-1)^2 - 2 = 4^n - 2^{n+1} - 1. Hence this is a type of "near-cube primes."
%H A117921 Charles R Greathouse IV, <a href="/A117921/b117921.txt">Table of n, a(n) for n = 1..10</a>
%H A117921 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Near-SquarePrime.html">Near-Square Prime.</a>
%F A117921 A098878 INTERSECTION A000040. {(2^k - 1)^3 - 2 iff prime}.
%e A117921 a(1) = (2^4 - 1)^3 - 2 = 3373 is prime.
%e A117921 a(2) = (2^5 - 1)^3 - 2 = 29789 is prime.
%e A117921 a(3) = (2^9 - 1)^3 - 2 = 133432829 is prime.
%e A117921 a(4) = (2^11 - 1)^3 - 2 = 8577357821 is prime.
%t A117921 Select[(2^Range[20]-1)^3-2,PrimeQ] (* _Harvey P. Dale_, Oct 22 2016 *)
%Y A117921 Cf. A091516, A091515, A098878, A091514.
%K A117921 nonn
%O A117921 1,1
%A A117921 _Jonathan Vos Post_, May 03 2006