Properties of the Number 20831

Twenty Thousand Eight Hundred Thirty-One

Basics

Value: 20830 → 20831 → 20832

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 37 × 563

Divisors: 1, 37, 563, 20831

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000101011111

Octal: 50537

Duodecimal: 1007B

Hexadecimal: 515f

Square: 433930561

Square Root: 144.3294841673038

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

The Wiener index of a benzenoid consisting of a linear chain of n hexagons. A143938

Define a pair of sequences c_n, d_n by c₀=0, d₀=1 and thereafter c_n = c_n-1+d_n-1, d_n = c_n-1+4·n+2; sequence here is c_n. A192751

Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0. A283887

G.f.: ∑_n>=0 xⁿ * ( (1+x)ⁿ + (1-x)ⁿ )ⁿ / 2ⁿ. A301308

a(n) = a(n-1) + 2·n² with a(1) = 1. A112524

Smallest number such that the sum of the digits of n·a(n) is greater than n. A269333

Number of length 3 0..n arrays with each partial sum starting from the beginning no more than one standard deviation from its mean. A244791

a(n) = a(n-1) + 3·a(n-2) -2·a(n-3) - 2·a(n-4), where a(0) = -1, a(1) = -1, a(2) = 2, a(3) = 1. A295852

s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = A000201 (lower Wythoff sequence), t = A001950 (upper Wythoff sequence). A25119

Number of walks within N³ (the first octant of Z³) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 0, -1), (0, 0, 1), (0, 1, 1), (1, 1, 0)}. A151178