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 A096140 #26 Aug 24 2025 11:34:52 %S A096140 0,1,3,10,29,81,220,589,1563,4126,10857,28513,74792,196041,513619, %T A096140 1345282,3522981,9224881,24153636,63239221,165569195,433476726, %U A096140 1134874513,2971168705,7778667024,20364889681,53316094755,139583544634 %N A096140 a(n) = sum of n Fibonacci numbers starting from F(n). %F A096140 a(n) = Fibonacci(2*n+1)-Fibonacci(n+1). - _Vladeta Jovovic_, Jul 17 2004 %F A096140 G.f.: x*(1-x+x^2)/((1-3*x+x^2)*(1-x-x^2)). a(n)=F(2n+1)-F(n+1). - Mario Catalani (mario.catalani(AT)unito.it), Jul 19 2004 %F A096140 Binomial transform of A005013. - _Michael Somos_, Apr 13 2012 %e A096140 a(4)= F(4) + F(5) + F(6) + F(7) = 3 + 5 + 8 + 13 = 29. %e A096140 x + 3*x^2 + 10*x^3 + 29*x^4 + 81*x^5 + 220*x^6 + 589*x^7 + ... %o A096140 (PARI) a(n)=sum(k=n,2*n-1,fibonacci(k)) %Y A096140 Cf. A005013. %K A096140 nonn,easy,changed %O A096140 0,3 %A A096140 _Amarnath Murthy_, Jul 16 2004 %E A096140 Extended by _Ray Chandler_, Jul 17 2004 %E A096140 a(0)=0 by _Michael Somos_, Apr 13 2012