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 A009056 #24 Nov 01 2024 09:35:34 %S A009056 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27, %T A009056 28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50, %U A009056 51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77 %N A009056 Numbers >= 3. %C A009056 Same as Pisot sequences E(3,4), P(3,4), T(3,4). See A008776 for definitions of Pisot sequences. %C A009056 Non-Fermat-exponents, positive integers n such that there are no solutions in positive integers of the equation a^n + b^n = c^n. - _Tanya Khovanova_, Jul 09 2011 %C A009056 Sums of twin primes. - _Charles R Greathouse IV_, Jun 21 2012 %H A009056 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A009056 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A009056 a(n) = n + 2. %F A009056 From _R. J. Mathar_, May 26 2008: (Start) %F A009056 O.g.f.: x*(3-2*x)/(1-x)^2. %F A009056 a(n) = A009005(n-1), n > 2. (End) %F A009056 From _Elmo R. Oliveira_, Oct 31 2024: (Start) %F A009056 E.g.f.: exp(x)*(x + 2) - 2. %F A009056 a(n) = 2*a(n-1) - a(n-2) for n > 2. %F A009056 a(n) = A055998(n) - A055998(n-1) = A020739(n-1)/2. (End) %t A009056 Range[3,80] (* _Harvey P. Dale_, Sep 26 2017 *) %o A009056 (PARI) a(n)=n+2 \\ _Charles R Greathouse IV_, Jun 21 2012 %Y A009056 Cf. A009005, A020739, A055998. %K A009056 easy,nonn %O A009056 1,1 %A A009056 _David W. Wilson_