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 A363374 #11 Dec 14 2024 15:54:52 %S A363374 8,11,13,15,17,18,21,23,25,30,32,33,34,35,36,37,40,44,54,58,60,61,71, %T A363374 73,92,95,101,102,106,144,160,164,183,200,209,210,216,241,244,270,273, %U A363374 274,281,293,309,313,344,365,422,430,461,475,477,480,504,509,556,579,597,609,612,631,650 %N A363374 Numbers k such that 2^k - 3 is a semiprime. %C A363374 The numbers 717, 720, 759 are also terms with 713 being the only remaining unknown below them. %e A363374 11 is a member because 2^11 - 3 = 2045 = 5 * 409 is a semiprime. %t A363374 Select[Range[700],PrimeOmega[2^#-3]==2&] (* _Harvey P. Dale_, Dec 14 2024 *) %Y A363374 Cf. A085724. %K A363374 nonn %O A363374 1,1 %A A363374 _Kevin P. Thompson_, May 29 2023