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 A108216 #9 Mar 20 2015 02:49:48
%S A108216 3,3,4,5,2,4,3,2,4,4,1,4,4,2,5,3,3,2,3,1,6,6,2,2,2,3,3,2,2,4,5,2,5,3,
%T A108216 2,2,3,2,3,5,2,4,2,1,3,4,2,3,4,2,3,5,3,4,3,4,3,2,4,2,0,2,4,3,1,1,3,3,
%U A108216 4,5,3,3,2,3,3,3,3,3,3,4,3,4,0,3,4,1,4,3,2,4,2,3,4,3,2,4,2,3,3,3,3,2,1,1,5
%N A108216 Number of semiprimes between 10n and 10n + 9.
%C A108216 a(60) = a(82) = a(142) = 0. - _Jonathan Vos Post_, Jun 16 2005
%e A108216 a(0) = 3 because between 0 and 9 there are three semiprimes: 4, 6 and 9.
%e A108216 a(1) = 3 because between 10 and 19 there are three semiprimes: 10, 14 and 15.
%t A108216 f[n_] := Sum[ PrimePi[n/Prime[i]] - (i - 1), {i, PrimePi[ Sqrt[n]]}]; Table[f[10n + 9] - f[Max[10n - 1, 0]], {n, 0, 104}] (* _Robert G. Wilson v_, _Ray Chandler_ *)
%Y A108216 Cf. A038800 number of primes between 10n and 10n+9.
%Y A108216 Cf. A064911, A066265, A072000.
%K A108216 nonn
%O A108216 0,1
%A A108216 _Giovanni Teofilatto_, Jun 16 2005
%E A108216 Edited and extended by _Ray Chandler_, Jul 07 2005