Properties of the Number 30681

Thirty Thousand Six Hundred Eighty-One

Basics

Value: 30680 → 30681 → 30682

Parity: odd

Prime: No

Previous Prime: 30677

Next Prime: 30689

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 7 × 487

Divisors: 1, 3, 7, 9, 21, 63, 487, 1461, 3409, 4383

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 111011111011001

Octal: 73731

Duodecimal: 15909

Hexadecimal: 77d9

Square: 941323761

Square Root: 175.15992692394

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

Coefficient of x⁴ in expansion of (1+x+x²)ⁿ. A5712

T(n,k)=1/6 the number of (n+2)X(k+2) 0..2 arrays with each 3X3 subblock containing one of one value, four of another, and four of the last. A184477

Triangle read by rows, T(n,k) = ∑_j=0..n (-1)^n-j*C(-j,-n)*S1(j,k), S1 the Stirling cycle numbers A132393, for n>=0 and 0<=k<=n. A269951

Expansion of e.g.f. log(1-x)² * exp(x) / (2 * (1-x)). A381024

a(n) = 58·n² - 1. A158668

Solution of the complementary equation a(n) = a(n-1) + a(n-2) + n·b(n), where a(0) = 2, a(1) = 4, b(0) = 1, b(1) = 3, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences. A296297

1/6 the number of (n+2)X5 0..2 arrays with each 3X3 subblock containing one of one value, four of another, and four of the last. A184471

1/6 the number of (n+2)X6 0..2 arrays with each 3X3 subblock containing one of one value, four of another, and four of the last. A184472

Numbers k such that 465·2^k+1 is prime. A318193

Triangle read by rows: T(n,k) is the coefficient of x^k in the ZZ polynomial of the hexagonal graphene flake O(3,3,n). A338158