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 A110606 #8 Oct 12 2019 12:00:04 %S A110606 4,6,8,12,13,17,18,21,22,27,28,29,38,41,45,47,50,53,60,63,70,73,77,81, %T A110606 82,83,91,92,97,98,99,101,102,109,113,118,127,129,130,131,133,134,139, %U A110606 140,141,143,145,150,157,159,167,171,172,178,181,183,188,193,194,195 %N A110606 Numbers n whose base 8 representations, interpreted as base 10 integers, are semiprimes. %C A110606 A108873 is the equivalent using base 3. A110602 is the equivalent using base 4. A110603 is the equivalent using base 5. A110604 is the equivalent using base 6. A110605 is the equivalent using base 7. A110607 is the equivalent using base 9. %e A110606 a(1) = 4 because 4 (base 8) = 4 (base 10) = 2 * 2, a semiprime (A001358). %e A110606 a(2) = 6 because 6 (base 8) = 6 (base 10) = 2 * 3. %e A110606 a(3) = 8 because 8 (base 8) = 10 and 10 (base 10) = 2 * 5. %e A110606 a(4) = 12 because 12 (base 8) = 14 and 14 (base 10) = 2 * 7. %e A110606 a(5) = 13 because 13 (base 8) = 15 and 15 (base 10) = 3 * 5. %t A110606 Select[Range[195], Plus @@ Last /@ FactorInteger[FromDigits[IntegerDigits[ #, 8]]] == 2 &] (* _Ray Chandler_, Aug 05 2005 *) %Y A110606 Cf. A001358, A007094, A108873, A110602, A110603, A110604, A110605, A110607. %K A110606 base,easy,nonn %O A110606 1,1 %A A110606 _Jonathan Vos Post_, Jul 30 2005 %E A110606 Extended by _Ray Chandler_, Aug 05 2005