In mathematics, a Fermat number, named after Pierre de Fermat, who first studied them, is a positive integer of the form = , where n is a nonnegative integer The first few Fermat numbers are 3, 5, 17, 257, , , , (sequence A in the OEIS) If 2 k 1 is prime and k > 0, then k must be a power of 2, so 2 k 1 is a Fermat number;Solve your math problems using our free math solver with stepbystep solutions Our math solver supports basic math, prealgebra, algebra, trigonometry, calculus and moreSolve your math problems using our free math solver with stepbystep solutions Our math solver supports basic math, prealgebra, algebra, trigonometry, calculus and more Find The Sum Of Series 3 7 13 21 31 Geeksforgeeks 2^n-1 combinations