15664
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 33480
- Proper Divisor Sum (Aliquot Sum)
- 17816
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7040
- Möbius Function
- 0
- Radical
- 1958
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 3
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 53
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Representation degeneracies for boson strings.at n=36A005291
- a(n) = F(n+2) - 2^[ (n+1)/2 ] - 2^[ n/2 ] + 1.at n=20A005673
- a(n+1) = a(n) converted to base 8 from base 7 (written in base 10).at n=35A023388
- a(n) = Fibonacci(2*n)-2^n+1.at n=11A047790
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A048149.at n=30A049712
- Number of primitive roots modulo prime(n)^2, where prime(n) is n-th prime.at n=40A104039
- a(n) = a(n - 1) + (n - 1)*a(n - 2).at n=10A122031
- a(1)=1, a(n)=a(n-1)+n if n odd, a(n)=a(n-1)+ n^2 if n is even.at n=43A140113
- a(n) is the sum of all possible pairs of the first n primes.at n=20A162867
- G.f.: x^3*(2*x-1) / ((1-x)*(1-x-x^2)*(1-2*x^2)).at n=22A174959
- a(n) = Fibonacci(n-2) + 2*a(n-2) - (n mod 2).at n=21A192727
- Recurrence a(n) = a(n-2) + n^M for M=4, starting with a(0)=0, a(1)=1.at n=10A231303
- Convolution of A006068 (inverse of Gray code) with itself: a(n) = Sum_{k=1..n+1} A006068(k) * A006068(1+n-k).at n=40A268721
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 307", based on the 5-celled von Neumann neighborhood.at n=28A271166
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 918", based on the 5-celled von Neumann neighborhood.at n=31A273748
- Triangle lc(n,k): the number of purely line-connected k-partitions of [n], n>=4, 3<=k<n.at n=36A305874
- Number of partitions of n having an integer median.at n=35A325347
- Partial sums of 4th powers of the even numbers.at n=5A330151
- a(n) is the determinant of the 2 X 2 matrix whose entries (when read by rows) are the n-th primes congruent to 1, 3, 5, 7 mod 8 respectively.at n=8A337145
- Array read by ascending antidiagonals: A(n, k) = (-1)^(n + k) * Sum_{j=0..k} (j!)^2 * Stirling1(n, j) * Stirling1(k, j).at n=49A379821