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 A086673 #11 Feb 16 2025 08:32:50 %S A086673 0,0,0,1,1,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, %T A086673 3,3,3,3,3,3,3,3,3,3,3,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,6,6,6,7,7,7,7, %U A086673 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,9,9,10,11,12,12,12,12 %N A086673 Number of right-truncatable semiprimes <= n. %H A086673 I. O. Angell and H. J. Godwin, <a href="http://dx.doi.org/10.1090/S0025-5718-1977-0427213-2">On Truncatable Primes</a>, Math. Comput. 31, 265-267, 1977. %H A086673 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Semiprime.html">Semiprime</a> %H A086673 <a href="/index/Tri#tprime">Index entries for sequences related to truncatable primes</a> %Y A086673 Cf. A085733, A001358. %K A086673 nonn %O A086673 1,6 %A A086673 _Reinhard Zumkeller_, Jul 27 2003