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 A070872 #12 Jun 29 2025 10:58:39
%S A070872 1,2,6,66,216,1159,2184
%N A070872 Numbers k such that A070871(k) = k.
%C A070872 Could be called nutritionally balanced numbers.
%t A070872 a[0] = 1; a[n_] := a[n] = If[ OddQ[n], a[n/2 - 1/2], a[n/2] + a[n/2 - 1]]; Do[ If[ a[n]*a[n - 1] == n, Print[n]], {n, 1, 5*10^6}]
%Y A070872 Cf. A002487, A070871.
%K A070872 nonn
%O A070872 1,2
%A A070872 _J. H. Conway_, May 17 2002
%E A070872 More terms from _David W. Wilson_, May 17 2002