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 A038445 #16 Mar 11 2025 03:44:15
%S A038445 111,1011,1101,1110,10011,10101,10110,11001,11010,11100,100011,100101,
%T A038445 100110,101001,101010,101100,110001,110010,110100,111000,1000011,
%U A038445 1000101,1000110,1001001,1001010,1001100,1010001,1010010,1010100,1011000,1100001,1100010,1100100
%N A038445 Sums of 3 distinct powers of 10.
%H A038445 Amiram Eldar, <a href="/A038445/b038445.txt">Table of n, a(n) for n = 1..10000</a>
%t A038445 Sort[Plus @@@ Subsets[10^Range[0, 6], {3}]] (* _Amiram Eldar_, Jul 12 2022 *)
%o A038445 (Python)
%o A038445 from math import isqrt, comb
%o A038445 from sympy import integer_nthroot
%o A038445 def A038445(n): return 10**((r:=n-1-comb((m:=integer_nthroot(6*n,3)[0])+(t:=(n>comb(m+2,3)))+1,3))-comb((k:=isqrt(b:=r+1<<1))+(b>k*(k+1)),2))+10**((a:=isqrt(s:=n-comb(m-(t^1)+2,3)<<1))+((s<<2)>(a<<2)*(a+1)+1))+10**(m+t+1) # _Chai Wah Wu_, Mar 10 2025
%Y A038445 Cf. A011557.
%Y A038445 Cf. A038444, A038446, A038447, A038448, A038449, A038450, A038451, A038452, A038453, A038454.
%K A038445 nonn,easy
%O A038445 1,1
%A A038445 _Olivier Gérard_