EntityQ1386491· pop 22· linked from 385 articlesPell numberSign in to savedenominator of close rational approximation to the square root of 2ConnectionsFibonacci sequenceEntityPerrin numberEntityprime numberEntityfractionEntityarithmetic progressionEntitycubeEntitylist of prime numbersEntityPell's equationEntitypower of twoEntityfigurate numberEntityLucas numberEntityautomorphic numberEntityNewman–Shanks–Williams primeEntitySmarandache–Wellin numberEntityStrobogrammatic numberEntitymathematicsEntityPlatoEntityLeonhard EulerEntityInternational Standard Book NumberEntitynatural numberEntityCategoriesInteger sequencesRecurrence relationsUnsolved problems in number theory