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 A090262 #7 Dec 20 2019 11:04:33 %S A090262 3,9,17,29,47,51,81,87,113,117,131,141,201,239,291,333,359,371,393, %T A090262 443,459,489,509,539,573,623,663,681,749,819,821,873,903,947,1071, %U A090262 1077,1161,1269,1533,1563,1589,1613,1637,1673,1767,1773,1821,1841,1883,1959,1977 %N A090262 Numbers n such that the strings n1n and 1n1 are both prime. %H A090262 Daniel Starodubtsev, <a href="/A090262/b090262.txt">Table of n, a(n) for n = 1..10000</a> %e A090262 9 is a member as 919 and 191 are both prime. %Y A090262 Cf. A090263, A090264, A090265. %K A090262 base,nonn %O A090262 1,1 %A A090262 _Amarnath Murthy_, Nov 28 2003 %E A090262 More terms from mohammed bouayoun (bouyao(AT)wanadoo.fr), Feb 02 2004