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 A176096 #1 Jun 01 2010 03:00:00 %S A176096 13,13313,1313813,131313113,13131313133,1131313131313,131313131313139, %T A176096 13131313131313913,1313131311313131313,113131313131313131313, %U A176096 13131313131313133131313,1313131131313131313131313 %N A176096 Smallest prime p = p(n) containing exactly n strings "13" (n = 1, 2, ...). %D A176096 E. I. Ignatjew, Mathematische Spielereien, Urania Verlag Leipzig/Jena/Berlin 1982 %D A176096 B. A. Kordemski: Koepfchen, Koepfchen! Mathematik zur Unterhaltung, Urania Verlag Leipzig/Jena/Berlin 1965 %e A176096 n = 1: prime(6) = 13 is 1st term of sequence %e A176096 prime(12268) = 131303 > 21313 = prime(2392) > 13313 = prime(1581) = p(2), 2nd term of sequence %e A176096 prime(857198) = 13131317 > 4131313 = prime(291796) > prime(102949) = 1341313 > 1313813 = prime() = p(3), 3rd term of sequence %e A176096 n = 13: 131131313131313131313131313 a 27-digit prime is 13th term of sequence %Y A176096 A037053, A037055, A037057, A037059, A037063, A037067 %K A176096 base,nonn %O A176096 1,1 %A A176096 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 08 2010