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 A159251 #8 Aug 13 2025 22:17:40
%S A159251 12,14,16,20,21,25,30,32,34,50,52,70,102,104,106,110,111,115,120,122,
%T A159251 124,133,140,142,160,200,201,203,205,210,212,214,221,230,232,250,300,
%U A159251 302,304,320,322,340,403,410,412,430,500,502,511,520,610,700,1001,1002
%N A159251 Composite numbers whose digit sum is a single-digit prime.
%C A159251 Numbers of (2..6)-digit terms are 12, 40, 105, 260, 543. - _Zak Seidov_, Apr 12 2009
%e A159251 250 is a composite number whose digit sum of 7 is a single-digit prime.
%t A159251 s={};Do[t=Total[IntegerDigits[n]];If[ !PrimeQ[n]&&(t-2)(t-3)(t-5)(t-7)== 0,AppendTo[s,n]],{n,7*10^3}];s (* _Zak Seidov_, Apr 12 2009 *)
%Y A159251 Cf. A002808 (composite numbers), A157496.
%K A159251 nonn,base,easy,less
%O A159251 1,1
%A A159251 _Parthasarathy Nambi_, Apr 06 2009
%E A159251 Extended, minor edits and keywords easy, less added by _Klaus Brockhaus_, Apr 12 2009
%E A159251 More terms from _Zak Seidov_, Apr 12 2009