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268 results

#223 · Algebra

Geometric sequence – find a₁

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#224 · Equations

Integer solutions of x² − y² = 84

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#225 · Arithmetic

Integers coprime to 30 up to 1000

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#226 · Arithmetic

GCD of Mersenne numbers

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#227 · Combinatorics

4-digit numbers with digit sum 9

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#228 · Arithmetic

Sum of 2-digit primes with digit sum 11

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#229 · Geometry

Law of cosines – triangle with 60° angle

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#230 · Functions

Functional equation f(x + 1/x)

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#231 · Combinatorics

5 boys and 3 girls in a row – no two girls adjacent

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#232 · Arithmetic

Number of divisors of 10!

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#233 · Arithmetic

Largest integer n with n² < 1000

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#234 · Equations

Product of three consecutive integers equals 120

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#235 · Probability

Probability of at least 2 red balls

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#236 · Geometry

Sum of sin²(1°) + sin²(2°) + … + sin²(90°)

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#237 · Combinatorics

Sum of k · k! for k = 1 to 6

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#238 · Algebra

Symmetric ratio when a + b + c = 0

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#239 · Arithmetic

Smallest prime p with p | 2^p + 1

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#240 · Combinatorics

Making change for $1 using 1¢, 5¢, 10¢

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#241 · Algebra

Minimum of x² + y² given xy = 100

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#242 · Equations

Positive integer solutions of 2^x = x²

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#243 · Algebra

Modulus |1 + i|⁸

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#244 · Algebra

Recurrence aₙ₊₁ = aₙ + 2n

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#245 · Combinatorics

Coefficient of x³ in (1 + x + x²)⁴

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#246 · Arithmetic

Primes of the form n² + 1 for n = 1 to 10

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#247 · Combinatorics

Alternating binomial sum

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#248 · Arithmetic

Perfect squares or cubes up to 1000

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#249 · Arithmetic

Sum of integers coprime to 1000

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#250 · Equations

Positive integer solutions of x² − y² = 2^100

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#251 · Arithmetic

Smallest n > 1 with (n+1) dividing sum of squares

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#252 · Combinatorics

Ordered triples (a, b, c) with product abc = 1000

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#253 · Combinatorics

Sum of all 3-digit numbers using digits 1, 2, 3

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#254 · Arithmetic

How many values of n² − n + 11 are prime for n = 1 to 10?

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#255 · Arithmetic

7^(7^7) mod 100

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#256 · Geometry

Lattice points in the disk x² + y² ≤ 25

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#257 · Algebra

Integer part of (√2 + 1)⁸

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#258 · Arithmetic

GCD of Fibonacci numbers F₁₀₀ and F₇₂

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#259 · Arithmetic

Perfect sixth powers up to 10^6

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#260 · Arithmetic

Sum of ⌊√k⌋ for k = 1 to 100

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#261 · Arithmetic

17^17 mod 100

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#262 · Combinatorics

Tiling a 2 × 10 grid with 1 × 2 dominoes

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#263 · Arithmetic

Sum of n ≤ 1000 with n² ≡ 1 (mod 1000)

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#264 · Combinatorics

Ordered representations of 100 as sum of 3 positive integers

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#265 · Arithmetic

Integers ≤ 1000 with an odd number of divisors

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#266 · Algebra

Maximum of xy + yz + zx given x + y + z = 1

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#267 · Combinatorics

C(200, 100) mod 5

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#268 · Arithmetic

Sophie Germain primes up to 30

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#269 · Combinatorics

Partitions of 10 into distinct positive parts

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#270 · Equations

Sum of integers n where n² − 19n + 99 is a perfect square

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