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 A239634 #6 Jul 24 2017 17:29:56 %S A239634 4,6,9,1,1,1,2,2,2,2,3,3,3,3,3,4,4,5,5,5,5,6,6,6,7,7,8,8,8,8,9,9,9,9, %T A239634 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2, %U A239634 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 %N A239634 Initial digits of semiprimes in decimal representation. %C A239634 a(n) = A000030(A001358(n)). %H A239634 Reinhard Zumkeller, <a href="/A239634/b239634.txt">Table of n, a(n) for n = 1..10000</a> %t A239634 First[IntegerDigits[#]]&/@Select[Range[300],PrimeOmega[#]==2&] (* _Harvey P. Dale_, Jul 24 2017 *) %o A239634 (Haskell) %o A239634 a239634 = a000030 . a001358 %Y A239634 Cf. A239639 (run lengths), A106146 (last digits). %K A239634 nonn,base %O A239634 1,1 %A A239634 _Reinhard Zumkeller_, Mar 23 2014