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 A060698 #4 Jul 20 2016 08:26:52 %S A060698 1,3,11,15,22,39,51,57,66,67,71,79,98,105,108,109,115,118,119,125,135, %T A060698 150,151,152,156,160,169,200,201,205,211,223,228,241,271,281,282,291, %U A060698 312,315,322,331,341,350,372,382,385,395,401,420,433,461,482,498,544 %N A060698 The sum of the first n composite numbers minus 1 is a prime. %t A060698 Composite[ n_Integer ] := (k = n + PrimePi[ n ] + 1; While[ k - PrimePi[ k ] - 1 != n, k++ ]; k); Select[ Range[ 1000 ], PrimeQ[ Sum[ Composite[ k ], {k, 1, #} ] - 1 ] & ] %t A060698 Position[Accumulate[Select[Range[700],CompositeQ]]-1,_?PrimeQ]//Flatten (* _Harvey P. Dale_, Jul 20 2016 *) %K A060698 nonn %O A060698 1,2 %A A060698 _Robert G. Wilson v_, Apr 20 2001