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 A038446 #20 Mar 11 2025 09:44:56
%S A038446 1111,10111,11011,11101,11110,100111,101011,101101,101110,110011,
%T A038446 110101,110110,111001,111010,111100,1000111,1001011,1001101,1001110,
%U A038446 1010011,1010101,1010110,1011001,1011010,1011100,1100011,1100101,1100110,1101001,1101010,1101100,1110001
%N A038446 Sums of 4 distinct powers of 10.
%H A038446 Amiram Eldar, <a href="/A038446/b038446.txt">Table of n, a(n) for n = 1..10000</a>
%t A038446 Total/@Subsets[10^Range[0,6],{4}]//Union (* _Harvey P. Dale_, Nov 07 2021 *)
%o A038446 (Python)
%o A038446 from itertools import islice
%o A038446 def A038446_gen(): # generator of terms
%o A038446 yield int(bin(n:=15)[2:])
%o A038446 while True: yield int(bin((n:=n^((a:=-n&n+1)|(a>>1)) if n&1 else ((n&~(b:=n+(a:=n&-n)))>>a.bit_length())^b))[2:])
%o A038446 A038446_list = list(islice(A038446_gen(),20)) # _Chai Wah Wu_, Mar 11 2025
%Y A038446 Cf. A011557, A157711 (primes subsequence).
%Y A038446 Cf. A038444, A038445, A038447, A038448, A038449, A038450, A038451, A038452, A038453, A038454.
%K A038446 nonn,easy
%O A038446 1,1
%A A038446 _Olivier Gérard_
%E A038446 Offset corrected by _Amiram Eldar_, Jul 12 2022