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 A074813 #5 Dec 15 2017 17:36:03 %S A074813 0,1,1,0,1,0,1,0,0,4,1,3,6,7,9,12,14,15,17,8,3,0,3,4,6,9,11,13,15,9,6, %T A074813 3,0,3,5,7,10,11,12,10,7,4,3,0,2,4,7,8,9,13,9,6,5,2,0,2,5,7,8,14,12,9, %U A074813 7,4,2,0,3,4,5,16,14,11,10,7,5,3,0,2,4,18,15,13,11,8,7,4,2,0,2,20,17 %N A074813 Number of primes between n and R(n) (inclusive), where R(n) (A004086) is the digit reversal of n. %C A074813 A060568 is the exclusive version of this sequence. %e A074813 The primes between n = 13 and 31, inclusive, are 13, 17, 19, 23, 29, 31; so a(13) = 6. %K A074813 base,easy,nonn %O A074813 1,10 %A A074813 _Jason Earls_, Sep 08 2002