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 A175013 #17 Jan 11 2025 16:26:15 %S A175013 4,6,9,1,5,6,3,4,7,8,6,7,8,11,12,10,13,6,10,12,13,8,11,15,11,14,10,13, %T A175013 14,15,10,12,13,14,7,3,7,10,11,4,5,6,12,7,8,6,7,8,10,11,11,14,15,8,13, %U A175013 16,15,16,12,14,16,14,3,4,5,7,8,11,6,7,8,10,11,12,5,10,10,12,13,15,10 %N A175013 Sum of digits of n-th semiprime. %H A175013 Harvey P. Dale, <a href="/A175013/b175013.txt">Table of n, a(n) for n = 1..1000</a> %F A175013 a(n) = A007953(A001358(n)). %p A175013 seq( A007953(A001358(n)),n=1..120) ; # _R. J. Mathar_, Aug 12 2010 %t A175013 Total[IntegerDigits[#]]&/@Select[Range[300],PrimeOmega[#]==2&] (* _Harvey P. Dale_, Jun 12 2012 *) %Y A175013 Cf. A001358, A007953. %K A175013 nonn,base %O A175013 1,1 %A A175013 _Juri-Stepan Gerasimov_, Apr 04 2010 %E A175013 Entries checked by _R. J. Mathar_, Aug 12 2010