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 A061153 #15 Jan 24 2023 06:42:03 %S A061153 47,94,188,257,376,383,766,881,1532,2897,3061,3064,4847,5297,5359, %T A061153 5794,5897,6122,6128,7013,7651,8423,9694,10223,10594,10718,11794, %U A061153 12244,13787,14026,14027,15302,16817,16846,18107,19249,19388,20446,21181,21188 %N A061153 Numbers k such that k*2^m+1 are composites for all exponents m in the range 0<=m<=k. %p A061153 filter:= n -> andmap(not isprime, [seq(n*2^m+1,m=0..n)]): %p A061153 select(filter, [$1..10000]); # _Robert Israel_, Sep 22 2019 %Y A061153 Cf. A061154, A061155, A061156, A061157, A061158. %K A061153 nonn %O A061153 1,1 %A A061153 _Patrick De Geest_, Apr 15 2001 %E A061153 More terms from _Robert Israel_, Sep 22 2019 %E A061153 Offset corrected by _Sean A. Irvine_, Jan 22 2023