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 A122824 #6 Jun 13 2016 08:33:13
%S A122824 1,4,9,8,10,12,24,24,32,15,46,24,27,34,25,40,44,46,51,54,53,46,54,60,
%T A122824 70,70,98,105,104,91,64,72,45,48,95,118,120,120,116,108,100,96,101,
%U A122824 118,102,144,123,86,76,81,136,138,143,112,132,131,153,160,171,169
%N A122824 Prime(semiprime(n)) - semiprime(prime(n)). Commutator [A000040,A001358] at n.
%H A122824 Giovanni Resta, <a href="/A122824/b122824.txt">Table of n, a(n) for n = 1..10000</a>
%F A122824 a(n) = A106349(n) - A106350(n).
%e A122824 a(1) = prime(semiprime(1)) - semiprime(prime(1)) = prime(4) - semiprime(2) = 7 - 6 = 1.
%e A122824 a(2) = prime(semiprime(2)) - semiprime(prime(2)) = prime(6) - semiprime(3) = 13 - 9 = 4.
%e A122824 a(3) = prime(semiprime(3)) - semiprime(prime(3)) = prime(9) - semiprime(5) = 23 - 14 = 9.
%e A122824 a(4) = prime(semiprime(4)) - semiprime(prime(4)) = prime(10) - semiprime(7) = 29 - 21 = 8.
%t A122824 sp = Select[Range[1000], PrimeOmega[#] == 2 &]; Table[ Prime[ sp[[i]]] - sp[[Prime[i]]], {i, PrimePi@ Length@ sp}] (* _Giovanni Resta_, Jun 13 2016 *)
%Y A122824 Cf. A000040, A001358, A106349, A106350.
%K A122824 easy,nonn
%O A122824 1,2
%A A122824 _Jonathan Vos Post_, Oct 23 2006
%E A122824 a(33)-a(54) corrected by and a(55)-a(60) from _Giovanni Resta_, Jun 13 2016