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 A147845 #5 Jun 02 2025 00:42:54 %S A147845 1,3,17,19,129,131,145,147,1025,1027,1041,1043,1153,1155,1169,1171, %T A147845 8193,8195,8209,8211,8321,8323,8337,8339,9217,9219,9233,9235,9345, %U A147845 9347,9361,9363,65537,65539,65553,65555 %N A147845 Odd positive integers a(n) such that for every odd integer m>=7 there exists a unique representation of the form m=a(p)+2a(q)+4a(r). %C A147845 Since, e.g., 27=17+2*3+4*1 and 17=a(3),3=a(2),1=a(1), then 27 has "coordinates" (3,2,1). Thus we have a one-to-one map of odd integers >=7 to the positive lattice points in the three-dimensional space. %F A147845 a(n)=2A033045(n-1)+1 %Y A147845 A145812 A145818 A033045 A033052 [From _Vladimir Shevelev_, Nov 19 2008] %K A147845 nonn %O A147845 1,2 %A A147845 _Vladimir Shevelev_, Nov 15 2008