Kynea number

Given n, compute 4n+2n+1-1 or (2n+1)2-2 or


Any of these formulas gives the Kynea numberMathworldPlanetmath for n.

The first few Kynea numbers are 7, 23, 79, 287, 1087, 4223, 16639, 66047, 263167, 1050623, 4198399, 16785407, 67125247 (listed in A093069 of Sloane’s OEIS). Every third Kynea number is divisible by 7, thus prime Kynea numbers can’t have n=3x+2 (except of course for n=2. The largest Kynea number known to be prime is (2281621+1)2-2, found by Cletus Emmanuel in November of 2005, using k-Sieve from Phil Comody and OpenPFGW.

Title Kynea number
Canonical name KyneaNumber
Date of creation 2013-03-22 16:13:13
Last modified on 2013-03-22 16:13:13
Owner Mravinci (12996)
Last modified by Mravinci (12996)
Numerical id 4
Author Mravinci (12996)
Entry type Definition
Classification msc 11N05