15256
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 28620
- Proper Divisor Sum (Aliquot Sum)
- 13364
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7624
- Möbius Function
- 0
- Radical
- 3814
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- 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
- Third row of Pascal-(1,2,1) array A081577.at n=15A081583
- Place n points on each of the three sides of a triangle, 3n points in all; a(n) = number of nondegenerate triangles that can be constructed using these points (plus the 3 original vertices) as vertices.at n=14A130748
- Number of 3-step one or two space at a time bishop's tours on an n X n board summed over all starting positions.at n=18A187047
- Number of (n+2) X 4 binary arrays avoiding patterns 001 and 110 in rows, columns and nw-to-se diagonals.at n=18A202441
- Last occurrence of n partitions in A204814.at n=18A205301
- Number of nX4 arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 nX4 array.at n=4A219377
- T(n,k)=Number of nXk arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 nXk array.at n=32A219381
- Number of 5Xn arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 5Xn array.at n=3A219385
- Number of n X n 0..7 matrices with each 2X2 subblock idempotent.at n=9A224664
- Sum of the denominators of the Farey series of order n (A006843).at n=42A240877
- Apply partial sum operator 5 times to primes.at n=10A254784
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 577", based on the 5-celled von Neumann neighborhood.at n=25A273024
- Iterations at which Langton's Ant living on triangular tiling reaches the distance of n from the origin for the first time.at n=35A275303
- Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 609", based on the 5-celled von Neumann neighborhood.at n=13A283286
- a(n) = Sum_{k=1..n, gcd(n,k) = 1} Stirling2(n,k).at n=9A308463
- Number of separable partitions of n in which the number of distinct (repeatable) parts <= 6.at n=36A325715