Bilgici G., Şentürk T.D.Bilgici, G, Senturk, TD2023-05-092023-05-092019-09-012019.01.010860-2107https://hdl.handle.net/20.500.12597/14490In this paper, we obtain a closed form for FΣi=1k, PΣi=1k and JΣi=1k for some positive integers k where Fr, Pr and Jr are the rth Fibonacci, Pell and Jacobsthal numbers, respectively. We also give three open problems for the general cases FΣi=1n, PΣi=1n and JΣi=1n for any arbitrary positive integer n.trueFibonacci numbers | Jacobsthal numbers | Pell numbersArticle10.2478/amsil-2019-000510.2478/amsil-2019-00052-s2.0-85095690560WOS:0006444740000045565332391-4238