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 A143384 #12 Jul 24 2023 10:27:22 %S A143384 1,5,1,5,11,11,17,19,23,97,127,145,167,269,767,479,3307,1453,18007, %T A143384 2357,599,17669,5527,3191,3251,70249,147773,39637 %N A143384 Duplicate of A139426. %C A143384 All primes certified using PFGW from Primeform group. %e A143384 (2^2-1)*(2^2-1+1)-1=11 prime 2^2-1=M(1) so a(1)=1 %e A143384 (2^3-1)*(2^3-1+1)-1=55 composite %e A143384 (2^3-1)*(2^3-1+3)-1=69 composite %e A143384 (2^3-1)*(2^3-1+5)-1=83 prime 2^3-1=M(2) so a(2)=5 %Y A143384 Cf. A000043 (Mersenne prime exponents), A143385. %K A143384 dead %O A143384 1,2 %A A143384 _Pierre CAMI_, Aug 11 2008 %E A143384 Missing terms 2357 and 599 inserted by _Jens Kruse Andersen_, Jul 30 2014