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 A050718 #11 Oct 26 2019 02:05:09 %S A050718 11,21,23,33,39,47,57,63,77,81,83,87,93,109,111,127,129,141,153,157, %T A050718 177,201,207,211,213,223,229,237,267,279,303,313,319,321,327,373,417, %U A050718 421,433,441,447,459,471,477,483,489,499,519,541,567,577,579,589,607 %N A050718 Inserting a digit '8' between adjacent decimal digits of n makes a prime. %C A050718 Arguably 2, 3, 5, and 7 should be in this sequence. - _Charles R Greathouse IV_, Sep 25 2012 %H A050718 Harvey P. Dale, <a href="/A050718/b050718.txt">Table of n, a(n) for n = 1..1000</a> %e A050718 177 becomes 1(8)7(8)7 which is the prime 18787. %t A050718 Select[Range[10,700],PrimeQ[FromDigits[Riffle[IntegerDigits[#],8]]]&] (* _Harvey P. Dale_, Sep 18 2013 *) %Y A050718 Cf. A050674, A050711-A050719. %K A050718 nonn,base %O A050718 1,1 %A A050718 _Patrick De Geest_, Aug 15 1999