# Problems

51 – 100 of 157
 Problem Title Likes Solvers Difficulty

#### Problem 52584. Easy Sequences 9: Faithful Pairs

Created by: Ramon Villamangca

1

14

#### Problem 44065. Number of even divisors of a given number

Created by: Jihye Sofia Seo

2

38

#### Problem 44289. Find two triangular numbers whose sum is input.

Created by: Mehmet OZC

2

84

#### Problem 44319. Write c^3 as sum of two squares a^2+b^2

Created by: Mehmet OZC

2

305

#### Problem 49582. Determine whether a square can be drawn on a grid of dots

Created by: ChrisR

4

9

#### Problem 55275. List the semiprimes

Created by: ChrisR

0

7

#### Problem 42888. Frobenius McNugget Factorization

Created by: Ned Gulley

15

18

#### Problem 45424. Amicable pair

Created by: Asif Newaz

2

6

#### Problem 55265. Parametric Array

Created by: Dyuman Joshi

1

5

#### Problem 56738. List unitary divisors of a number

Created by: ChrisR

0

6

#### Problem 56743. Count the unitary divisors of a number

Created by: ChrisR

0

5

#### Problem 46003. Compute Khinchin's constant

Created by: ChrisR

2

11

#### Problem 2734. N-th Odious

Created by: Jan Orwat

3

158

#### Problem 52814. Easy Sequences 27: Product of Radicals of Integers

Created by: Ramon Villamangca

2

6

#### Problem 656. Calculate Euler's phi function

Created by: Freddy

1

82

#### Problem 49788. Carmichael Number

Created by: Gifari Zulkarnaen

3

9

#### Problem 55360. Magical Land

Created by: Dyuman Joshi

0

6

#### Problem 52679. Easy Sequences 16: Volume of Embedded Octahedron

Created by: Ramon Villamangca

1

7

#### Problem 46099. Identify full reptend primes

Created by: ChrisR

0

10

#### Problem 51715. Iterate the sum of divisors and totient

Created by: ChrisR

2

8

#### Problem 2735. Binary Neighbourhood

Created by: Jan Orwat

2

64

Created by: HH

3

17

#### Problem 45831. Compute the Bernoulli numbers

Created by: ChrisR

0

10

#### Problem 54700. Leyland Primes

Created by: Dyuman Joshi

1

5

#### Problem 52497. Easy Sequences 3: Prime 44-number Squares

Created by: Ramon Villamangca

1

22

#### Problem 2797. modular arithmetic

Created by: rifat

2

44

#### Problem 54680. Determine whether a number is practical

Created by: ChrisR

2

5

#### Problem 2595. Polite numbers. Politeness.

Created by: Jan Orwat

7

142

#### Problem 46087. Investigate the frequency of last non-zero digits of primorials

Created by: ChrisR

1

8

#### Problem 2848. Digital Neighbourhood

Created by: Jan Orwat

2

58

#### Problem 45994. Investigate the frequency of last digits of prime numbers

Created by: ChrisR

3

12

#### Problem 52804. Easy Sequences 29: Odd proper divisors of odd proper divisors

Created by: Ramon Villamangca

1

4

#### Problem 52809. Easy Sequences 28: Sum of Radicals of Integers

Created by: Ramon Villamangca

2

7

#### Problem 52849. Easy Sequences 34: Modified Pascal's Triangle

Created by: Ramon Villamangca

1

6

#### Problem 53109. Easy Sequences 52: Non-squarable Rectangles

Created by: Ramon Villamangca

2

2

#### Problem 53130. Easy Sequences 55: "Ugly" Rectangles?

Created by: Ramon Villamangca

2

3

#### Problem 53725. Easy Sequences 56: Counting "Ugly" Numbers

Created by: Ramon Villamangca

3

5

#### Problem 53755. Easy Sequence 61: Wide Pythagorean Triangles

Created by: Ramon Villamangca

0

2

#### Problem 53760. Easy Sequences 62: Sum of Omega-3 Function

Created by: Ramon Villamangca

2

2

#### Problem 42889. Should Mr McNugget even get out of bed today?

Created by: James

1

11

#### Problem 1825. Find all vampire fangs

Created by: Andrew Newell

2

52

#### Problem 45939. Estimate π from certain values of the zeta function

Created by: ChrisR

0

6

#### Problem 46066. Evaluate the logarithmic integral

Created by: ChrisR

1

12

#### Problem 46582. Find jumping medalists

Created by: ChrisR

3

13

#### Problem 57293. Compute the unitary totient of a number

Created by: ChrisR

1

1

#### Problem 53940. Easy Sequences 66: Fractional Part of Sum of Consecutive Powers over a Prime

Created by: Ramon Villamangca

1

2

#### Problem 53990. Classify product/digit-sum sequences

Created by: ChrisR

4

7

#### Problem 54740. Count the ways to make Scorigami

Created by: ChrisR

1

2

#### Problem 55335. Generate Bernoulli polynomials

Created by: ChrisR

0

5

#### Problem 56220. Easy Sequences 75: Easy as Pisano Pi

Created by: Ramon Villamangca

1

6

51 – 100 of 157