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 A352776 #22 Apr 03 2022 09:56:47 %S A352776 0,1,3,10,11,18,19,22,23,25,34,35,38,39,41,49,53,54,66,67,70,71,73,81, %T A352776 85,86,97,101,102,110,116,117,119,130,131,134,135,137,145,149,150,161, %U A352776 165,166,174,180,181,183,193,197,198,206,212,213,215,228,229,231,236,237,243,246,247,258,259,262,263,265,273 %N A352776 Numbers k such that w(k + w(k)) = w(k), where w(k) is the binary weight of k, A000120(k). %C A352776 w(k + w(k)) - w(k) = 0 this sequence, w(k + w(k)) - w(k) = 2 for k = 4*j, where A000120(j) = 3. %F A352776 k : A000120(A092391(k)) = A000120(k); A348367(k) = A000120(k). %e A352776 k = 18; A000120(18 + A000120(18)) = A000120(18), thus k = 18 is a term. %t A352776 w[n_] := DigitCount[n, 2, 1]; Select[Range[0, 300], w[# + w[#]] == w[#] &] (* _Amiram Eldar_, Apr 02 2022 *) %o A352776 (Python) %o A352776 def w(n): return bin(n).count("1") %o A352776 def ok(n): wn = w(n); return w(n + wn) == wn %o A352776 print([k for k in range(274) if ok(k)]) # _Michael S. Branicky_, Apr 02 2022 %Y A352776 Cf. A000120, A092391, A348367. %K A352776 nonn,base,easy %O A352776 1,3 %A A352776 _Ctibor O. Zizka_, Apr 02 2022