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 A116050 #4 May 15 2013 08:58:33 %S A116050 1,4,5,8,10,16,18,22,23,27,29,32,36,41,46,50,53,65,66,70,94,99,101, %T A116050 106,111,113,125,129,131,137,171,183,195,197,200,201,203,209,210,221, %U A116050 233,237,239,245,251,269,275,299,301,309,317,321,322,327,329,333,335 %N A116050 n+sigma(n)+sigma(sigma(n)) is a prime. %H A116050 Harvey P. Dale, <a href="/A116050/b116050.txt">Table of n, a(n) for n = 1..1000</a> %e A116050 8 + sigma(8) + sigma(sigma(8)) = 47. %t A116050 dsQ[n_]:=Module[{dsn=DivisorSigma[1,n]},PrimeQ[n+dsn+DivisorSigma[1,dsn]]]; Select[Range[400],dsQ] (* _Harvey P. Dale_, May 15 2013 *) %Y A116050 Cf. A078762. %K A116050 nonn %O A116050 1,2 %A A116050 _Giovanni Resta_, Feb 13 2006