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 A128092 #22 Aug 24 2023 12:06:14 %S A128092 2,4,6,16,30,60,126,256,504,1020,2046,4092,8190,16380,32760,65536, %T A128092 131070,262134,524286,1048560,2097144,4194300,8388606,16777200, %U A128092 33554425,67108860,134217702,268435440,536870910,1073741820,2147483646 %N A128092 a(n) = largest multiple of n which is <= 2^n. %F A128092 a(n) = n*floor(2^n/n) = n*A000799(n). %F A128092 a(n) = 2^n - (2^n mod n). - _Chai Wah Wu_, Aug 24 2023 %p A128092 a:=n->n*floor(2^n/n): seq(a(n),n=1..37); # _Emeric Deutsch_, Feb 16 2007 %t A128092 f[n_] := n*Floor[2^n/n];Array[f, 33] (* _Ray Chandler_, Feb 19 2007 *) %o A128092 (Python) %o A128092 def A128092(n): return (m:=1<<n)-(m%n) # _Chai Wah Wu_, Aug 24 2023 %Y A128092 Cf. A128093, A000799. %Y A128092 Cf. A000079, A015910. %K A128092 nonn %O A128092 1,1 %A A128092 _Leroy Quet_, Feb 14 2007 %E A128092 Extended by _Emeric Deutsch_ and _Ray Chandler_, Feb 19 2007