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 A154115 #23 Jan 25 2025 18:58:04 %S A154115 0,2,4,8,10,14,16,20,26,28,34,38,40,44,50,56,58,64,68,70,76,80,86,94, %T A154115 98,100,104,106,110,124,128,134,136,146,148,154,160,164,170,176,178, %U A154115 188,190,194,196,208,220,224,226,230,236,238,248,254,260,266,268,274,278 %N A154115 Numbers n such that n + 3 is prime. %H A154115 G. C. Greubel, <a href="/A154115/b154115.txt">Table of n, a(n) for n = 1..2000</a> %F A154115 a(n) = A086801(n+1). - _R. J. Mathar_, May 09 2010 %e A154115 a(2) = 2 since (2 + 2)^2 - (2 + 1)^2 - 2 = 5. %p A154115 A154115 := proc(n) ithprime(n+1)-3 ; end proc: # _R. J. Mathar_, May 09 2010 %t A154115 a[n_]:=(n+2)^2-(n+1)^2-n;lst={};Do[If[PrimeQ[a[n]],AppendTo[lst,n]],{n,6!}];lst %t A154115 Select[Range[0,300],PrimeQ[(#+2)^2-(#+1)^2-#]&] (* _Harvey P. Dale_, Nov 06 2013 *) %t A154115 Prime[Range[2,100]]-3 (* _Harvey P. Dale_, Jul 15 2017 *) %o A154115 (Magma) [n: n in [0..500] | IsPrime((n+2)^2-(n+1)^2-n)]; // _Vincenzo Librandi_, Nov 26 2010 %o A154115 (PARI) is(n)=isprime(n+3) \\ _Charles R Greathouse IV_, Sep 02 2016 %Y A154115 Cf. A140719, A005097, A154111, A154112, A154113. %Y A154115 Cf. A067076 (a(n-1)/2). %K A154115 nonn,easy %O A154115 1,2 %A A154115 _Vladimir Joseph Stephan Orlovsky_, Jan 04 2009 %E A154115 New name based on a comment by _Franklin T. Adams-Watters_, Jan 30 2009