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 A227956 #8 Dec 11 2013 22:55:29 %S A227956 3,4,6,8,12,14,18,20,24,30,32,38,44,62 %N A227956 Possible lengths of minimal prime number rulers. %C A227956 A ruler is a prime number ruler provided all its interior marks are on a prime number position. A ruler is called complete when any positive integer distance up to the length of the ruler can be measured. A complete ruler is called minimal when any subsequence of its marks is not complete for the same length. A complete ruler is perfect, if there is no complete ruler with the same length which possesses fewer marks. A perfect ruler is minimal (but not conversely). For definitions, references and links related to complete rulers see A103294. %C A227956 The possible lengths of perfect prime number rulers are: 3, 4, 6, 8, 14, 18, 20, 24, 30, 32. There are 102 prime number rulers in total, 28 of which are minimal prime number rulers and 12 perfect prime number rulers. %C A227956 a(n) is a finite subsequence of A008864. %H A227956 Peter Luschny, <a href="http://oeis.org/wiki/User:Peter_Luschny/PerfectRulers">Perfect and optimal rulers</a>. %H A227956 Naoyuki Tamura, <a href="http://bach.istc.kobe-u.ac.jp/lect/ProLang/org/pnr.pdf">Complete List of Prime Number Rulers</a>, Information Science and Technology Center, Kobe University, 2013. %e A227956 [0, 2, 3, 5, 7, 11, 17, 18] is a minimal and also a perfect prime number ruler. %e A227956 [0, 2, 3, 5, 7, 11, 13, 19, 20] is a minimal but not a perfect prime number ruler. %K A227956 nonn,fini,full %O A227956 1,1 %A A227956 _Peter Luschny_, Aug 26 2013