Euler problems/61 to 70
Find the sum of the only set of six 4-digit figurate numbers with a cyclic property.
problem_61 = undefined
Find the smallest cube for which exactly five permutations of its digits are cube.
problem_62 = undefined
How many n-digit positive integers exist which are also an nth power?
problem_63 = undefined
How many continued fractions for N ≤ 10000 have an odd period?
problem_64 = undefined
Find the sum of digits in the numerator of the 100th convergent of the continued fraction for e.
problem_65 = undefined
Investigate the Diophantine equation x2 − Dy2 = 1.
problem_66 = undefined
Using an efficient algorithm find the maximal sum in the triangle?
problem_67 = undefined
What is the maximum 16-digit string for a "magic" 5-gon ring?
problem_68 = undefined
Find the value of n ≤ 1,000,000 for which n/φ(n) is a maximum.
problem_69 = undefined
Investigate values of n for which φ(n) is a permutation of n.
problem_70 = undefined