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 A360372 #19 Feb 14 2023 02:40:01
%S A360372 1,11,21,23,37,461,94101,14958901,16364133,134375017,192594821,
%T A360372 416095237,4074380993,82482257999
%N A360372 Numbers k >= 1 such that k divides Sum_{i=1..k} A007088(i).
%C A360372 The arithmetic mean of the first k binary numbers, taken as decimal numbers, is an integer.
%e A360372 k = 11: (1 + 10 + 11 + 100 + 101 + 110 + 111 + 1000 + 1001 + 1010 + 1011) / 11 = 406, thus 11 is a term.
%t A360372 s = 0; seq = {}; Do[s += FromDigits[IntegerDigits[k, 2]]; If[Divisible[s, k], AppendTo[seq, k]], {k, 1, 1000}]; seq (* _Amiram Eldar_, Feb 04 2023 *)
%Y A360372 Cf. A007088, A067894.
%K A360372 nonn,more
%O A360372 1,2
%A A360372 _Ctibor O. Zizka_, Feb 04 2023
%E A360372 a(7)-a(13) from _Amiram Eldar_, Feb 04 2023
%E A360372 a(14) from _Bert Dobbelaere_, Feb 14 2023