%I #12 Mar 11 2023 15:32:51
%S 36,36,54,45,36,27,36,27,54,45,396,99,198,792,198,396,693,792,792,594,
%T 693,198,396,594,99,297,99,396,297,693,99,99,594,198,297,396,594,198,
%U 594,198,198,198,99,495,99,99,297,99,297,297,396,99,198,297
%N Absolute value of difference between the n-th "emirpimes" A097393(n) and its reversal.
%C An emirpimes ("semiprime" spelled backwards) is a semiprime whose (base 10) reversal is a different semiprime. The first such number is 15, because 15 reversed is 51 and both 15 and 51 are semiprimes (i.e., 15 = 3*5 and 51 = 3*17). Because of the decimal base, each value must be a multiple of 9.
%H Post, Jonathan Vos, <a href="http://mathworld.wolfram.com/Emirpimes.html">Emirpimes</a>. From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein.
%F a(n) = |A097393(n) - R(A097393(n))| = |A097393(n) - A004086(A097393(n))|.
%e a(1) = absolute value of first emirpimes versus its reversal = |15 - 51| = |-36| = 36.
%e a(2) = |26 - 62| = |-36| = 36.
%e a(3) = |39 - 93| = |-54| = 54.
%e a(4) = |49 - 94| = |-45| = 45.
%t Abs[#-IntegerReverse[#]]&/@Select[Range[800],!PalindromeQ[#]&&PrimeOmega[ #] == PrimeOmega[IntegerReverse[#]]==2&] (* _Harvey P. Dale_, Mar 11 2023 *)
%Y Cf. A001358, A004086, A097393.
%K nonn,base,easy
%O 1,1
%A _Jonathan Vos Post_, Oct 08 2012