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 A119529 #29 Jul 01 2024 13:10:01
%S A119529 3,4,8,28,52,56,82,1472,1484,8669,10886,20804,32606,36392,57005,61628,
%T A119529 88652,89732
%N A119529 Numbers k such that Sum_{j=1..k-1} j*2^(j-1) is prime.
%t A119529 s = 0; Do[s += (x-1)*2^(x-1)/2; If[PrimeQ[s], Print[x]], {x, 10^4}] (* _Ryan Propper_, Jan 01 2007 *)
%t A119529 Select[Range[1, 2000], PrimeQ[2^(#-1)*(#-2) + 1] &] (* _Vaclav Kotesovec_, Jul 01 2024 *)
%Y A119529 Cf. A000523, A125569.
%K A119529 nonn,more
%O A119529 1,1
%A A119529 _Jorge Coveiro_, Jul 27 2006
%E A119529 a(10) from _Ryan Propper_, Jan 01 2007
%E A119529 Name simplified by _Jon E. Schoenfield_, Sep 23 2018
%E A119529 a(11)-a(14) from _Amiram Eldar_, Dec 01 2021
%E A119529 a(15)-a(16) from _Michael S. Branicky_, May 04 2023
%E A119529 a(17)-a(18) from _Michael S. Branicky_, Jun 30 2024