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 A281377 #8 May 22 2025 10:21:45 %S A281377 1,3,1,23,21,19,17,15,13,11,9,7,5,3,1,735,733,731,729,727,725,723,721, %T A281377 719,717,715,713,711,709,707,705,1343,1341,1339,1337,1335,1333,1331, %U A281377 1329,1327,1325,1323,1321,1319,1317,1315,1313,1311,1309,1307,1305,1303,1301,1299,1297,1295,1293 %N A281377 Write n in Elias's omega code, interchange the 1's and 0's and convert it back to decimal. %H A281377 Indranil Ghosh, <a href="/A281377/b281377.txt">Table of n, a(n) for n = 1..10000</a> %e A281377 For n = 10, the Elias omega code for n is '1110100', which after interchanging the 1's and 0's becomes '0001011'. Now, 1011_2 = 11_10. So, a(10) = 11. %o A281377 (Python) %o A281377 def a(n): %o A281377 s="" %o A281377 for i in A281193(n): %o A281377 if i=="1": %o A281377 s+="0" %o A281377 else: %o A281377 s+="1" %o A281377 return int(s, 2) %Y A281377 Cf. A035327, A054429 (n is converted to Elias gamma code, the 1's and 0's are interchanged and the code is converted back to decimal, for n>1), A281193, A281313. %K A281377 nonn,base %O A281377 1,2 %A A281377 _Indranil Ghosh_, Jan 21 2017