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 A162948 #8 Apr 17 2019 03:44:20
%S A162948 2,3,5,7,20,21,110,111,133,200,201,209,247,407,481,511,629,803,1010,
%T A162948 1011,1100,1101,1141,1387,1417,1651,1679,1853,2000,2001,2023,2119,
%U A162948 2159,2353,2401,2771,3031,3077,3097,3383,3439,3523,3749,3781,4577,4607,4913,5149,5161
%N A162948 Numbers with a sum of digits equal to their smallest prime factor.
%H A162948 Robert Israel, <a href="/A162948/b162948.txt">Table of n, a(n) for n = 1..10000</a>
%F A162948 {n: A007953(n) = A020639(n)}. - _R. J. Mathar_, Jul 19 2009
%e A162948 133 is in the sequence because 1 + 3 + 3 = 7 and 7 is the smallest prime factor of 133.
%p A162948 A007953 := proc(n) local d; add(d,d=convert(n,base,10)) ; end:
%p A162948 A020639 := proc(n) min(op(numtheory[factorset](n) )) ; end:
%p A162948 isA162948 := proc(n) RETURN( A007953(n) = A020639(n)) ; end:
%p A162948 for n from 1 to 6000 do if isA162948(n) then printf("%d,",n) ; fi; od: # _R. J. Mathar_, Jul 19 2009
%Y A162948 Cf: A007953, A020639.
%Y A162948 Even terms: A069537.
%K A162948 nonn,base
%O A162948 1,1
%A A162948 _Claudio Meller_, Jul 18 2009
%E A162948 Single-digit primes added by _R. J. Mathar_, Jul 19 2009