A281377 - OEIS

%I #6 Jan 22 2017 21:50:10

%S 1,3,1,23,21,19,17,15,13,11,9,7,5,3,1,735,733,731,729,727,725,723,721,

%T 719,717,715,713,711,709,707,705,1343,1341,1339,1337,1335,1333,1331,

%U 1329,1327,1325,1323,1321,1319,1317,1315,1313,1311,1309,1307,1305,1303,1301,1299,1297,1295,1293

%N Write n in Elias's omega code, interchange the 1's and 0's and convert it back to decimal.

%H Indranil Ghosh, <a href="/A281377/b281377.txt">Table of n, a(n) for n = 1..10000</a>

%e 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 (Python)

%o def a(n):

%o ....s=""

%o ....for i in A281193(n):

%o ........if i=="1":

%o ............s+="0"

%o ........else:

%o ............s+="1"

%o ....return int(s, 2)

%Y 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 nonn,base

%O 1,2

%A _Indranil Ghosh_, Jan 21 2017