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 A247104 #12 Feb 16 2025 08:33:23
%S A247104 3,5,7,31,42,53,86,97,110,143,154,165,187,209,211,222,233,255,266,277,
%T A247104 299,310,323,334,345,367,389,411,413,435,446,457,479,501,514,547,569,
%U A247104 591,602,613,615,626,659,670,681,703,714,727,749,771,782,793,815,817
%N A247104 Squarefree self-numbers.
%C A247104 Squarefree numbers not expressible as the sum of an integer and its digit sum;
%C A247104 intersection of A005117 and A003052.
%H A247104 Reinhard Zumkeller, <a href="/A247104/b247104.txt">Table of n, a(n) for n = 1..10000</a>
%H A247104 D. R. Kaprekar, <a href="/A003052/a003052_2.pdf">The Mathematics of the New Self Numbers</a> [annotated and scanned]
%H A247104 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SelfNumber.html">Self Number</a>
%H A247104 Wikipedia, <a href="http://en.wikipedia.org/wiki/Self_number">Self number</a>
%F A247104 A008966(a(n)) * (1 - A230093(a(n))) = 1.
%t A247104 nmax = 1000;
%t A247104 Select[Complement[Range[nmax], Union[Table[n + Total[IntegerDigits[n]], {n, 1, nmax}]]], #>1 && SquareFreeQ[#]&] (* _Jean-François Alcover_, Jan 08 2020, after _T. D. Noe_ in A003052 *)
%o A247104 (Haskell)
%o A247104 a247104 n = a247104_list !! (n-1)
%o A247104 a247104_list = filter ((== 1) . a008966) $ tail a003052_list
%Y A247104 Cf. A005117, A003052, A008966, A062028, A006378 (subsequence), A249044.
%K A247104 nonn,base
%O A247104 1,1
%A A247104 _Reinhard Zumkeller_, Nov 18 2014