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 A278699 #9 Dec 03 2016 13:10:32
%S A278699 2,3,7,11,19,23,43,59,67,71,83,107,131,139,151,199,211,251,263,467,
%T A278699 523,571,619,643,787,811,827,839,907,919,967,1019,1031,1091,1163,1223,
%U A278699 1667,1811,1931,2131,2179,2311,2887,3067,3079,3083,3203,3271,3323,3539,3643,3691,3911,4091,4099,4139
%N A278699 Primes p such that every suffix of the base-4 representation of p is a prime.
%C A278699 All numbers in the sequence are of the form 4n+3, except the number 2.
%e A278699 23 is in the sequence, since 23 is prime, and the suffixes of 23 (113 base 4), 13 base 4 (7 base 10) and 3, are all prime.
%t A278699 With[{b = 4}, Select[Prime@ Range[10^3], Function[k, Times @@ Boole@ Map[PrimeQ@ FromDigits[Take[k, -#], b] &, Range[Length@ k - 1]] == 1]@ IntegerDigits[#, b] &]] (* _Michael De Vlieger_, Dec 01 2016 *)
%K A278699 nonn,base
%O A278699 1,1
%A A278699 _Randy L. Ekl_, Nov 26 2016