# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a334042 Showing 1-1 of 1 %I A334042 #24 Apr 13 2020 18:19:25 %S A334042 1,0,3,6,15,6,27,14,63,46,27,6,111,86,59,30,255,222,187,150,111,70,27, %T A334042 494,447,398,347,294,239,182,123,62,1023,958,891,822,751,678,603,526, %U A334042 447,366,283,198,111,22,1979,1886,1791,1694,1595,1494,1391,1286,1179 %N A334042 Write n^2 in binary, interchange 0's and 1's, convert back to decimal. %H A334042 Daniel Starodubtsev, Table of n, a(n) for n = 0..10000 %F A334042 a(n) = A035327(A000290(n)). - _Alois P. Heinz_, Apr 13 2020 %p A334042 a:= n-> (l-> add((1-l[i])*2^(i-1), i=1..nops(l)))(convert(n, base, 2)): %p A334042 seq(a(n), n=0..60); # _Alois P. Heinz_, Apr 13 2020 %t A334042 a[n_] := FromDigits[1 - IntegerDigits[n^2, 2], 2]; Array[a, 55, 0] (* _Amiram Eldar_, Apr 13 2020 *) %o A334042 (Python) %o A334042 def oppsquare(n): %o A334042 s = str(bin(n**2))[2:] %o A334042 t = '' %o A334042 for i in range(len(s)): %o A334042 if s[i] == '0': %o A334042 t += '1' %o A334042 else: %o A334042 t += '0' %o A334042 return int(t,2) %o A334042 (PARI) a(n)=if(n, my(s=n^2); bitneg(s,exponent(s)+1), 1) \\ _Charles R Greathouse IV_, Apr 13 2020 %o A334042 (Python) %o A334042 def A334042(n): %o A334042 return 2**(len(bin(n**2))-2)-1-n**2 # _Chai Wah Wu_, Apr 13 2020 %Y A334042 Cf. A000290, A035327. %K A334042 nonn,base,easy %O A334042 0,3 %A A334042 _Christoph Schreier_, Apr 13 2020 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE