MathDB

4

Part of 2008 India Regional Mathematical Olympiad

Problems(2)

Counting 6 digit numbers with conditions

Source: (Indian) RMO 2008 Problem 4

11/9/2008
Find the number of all 6 6-digit natural numbers such that the sum of their digits is 10 10 and each of the digits 0,1,2,3 0,1,2,3 occurs at least once in them. [14 points out of 100 for the 6 problems]
combinatorics unsolvedcombinatoricsRMO
Number Theory

Source: Excursion

6/25/2020
Determine all the natural numbers nn such that 2121 divides 22n+2n+1.2^{2^{n}}+2^n+1.
number theoryDivisibilityNatural Numbers