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 A217591 #18 Jul 12 2024 14:18:13
%S A217591 18,54,18,36,54,36,18,18,594,198,792,594,594,792,792,198,396,396,594,
%T A217591 594,594,198,396,198,396,594,594,198,198,198,792,594,198,792,594,792,
%U A217591 7992,180,270,2268,540,8532,810,6804,1908,7902,360,2358,630,2718,180,1908,5904,1998,7992,90,6084,8172,8262,8442
%N A217591 Absolute differences between emirps (A006567) and their reversals.
%C A217591 This is unsorted, and in order of appearance of emirps.
%C A217591 All values are multiples of 18 (A008600). - _Charles R Greathouse IV_, Oct 15 2012
%F A217591 a(n) = | A006567(n) - R(A006567(n)) | = | A006567(n) - A004086(A006567(n)) |.
%e A217591 a(1) = absolute value of first emirp versus its reversal = |13 - 31| = |-18| = 18.
%e A217591 a(2) = |17 - 71| = |-54| = 54.
%e A217591 a(3) = |31 - 13| = |18| = 18.
%e A217591 a(4) = |37 - 73| = |-36| = 36.
%p A217591 R:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||n):
%p A217591 q:= n-> isprime(n) and (p-> p<>n and isprime(p))(R(n)):
%p A217591 map(x-> abs(x-R(x)), select(q, [$2..1280]))[]; # _Alois P. Heinz_, Jul 12 2024
%Y A217591 Cf. A004086, A006567, A008600, A217286, A217386, A217387.
%K A217591 nonn,base,easy
%O A217591 1,1
%A A217591 _Jonathan Vos Post_, Oct 07 2012
%E A217591 Corrected and more terms from _Georg Fischer_, Jul 12 2024