15526
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
- 26640
- Proper Divisor Sum (Aliquot Sum)
- 11114
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6648
- Möbius Function
- -1
- Radical
- 15526
- Omega Function (Ω)
- 3
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 146
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- Number of partitions of n into parts not of the form 15k, 15k+6 or 15k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 6 are greater than 1.at n=38A035960
- Number of partitions of n into sums of products.at n=27A066815
- Centered 15-gonal numbers: a(n) = (15*n^2 - 15*n + 2)/2.at n=45A069128
- Trisection of A007294.at n=37A073471
- Expansion of 1/(x^10*p(1/x)), where p(x) = x^11 + x^10 - 11*x^9 - 11*x^8 + 42*x^7 + 40*x^6 - 66*x^5 - 54*x^4 + 42*x^3 + 24*x^2 - 8*x - 1 is a Salem polynomial.at n=11A143478
- Triangle T(n,k), read by rows, given by (2,1/2,-1/2,0,0,0,0,0,0,0,...) DELTA (2,-1/2,1/2,0,0,0,0,0,0,0,...) where DELTA is the operator defined in A084938.at n=40A201972
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 358", based on the 5-celled von Neumann neighborhood.at n=39A271412
- 2..a(n) is the smallest range in which the most common value of Omega(k) is n, where Omega(k) is the number of prime factors of k (A001222).at n=2A273381
- Consider the race between primes, semiprimes, 3-almost primes, ... k-almost primes; sequence indicates when one overtakes another to give a new race leader.at n=4A276176
- Sum of the largest parts of the partitions of n into 5 parts.at n=38A308827
- Sum of the fourth largest parts in the partitions of n into 7 parts.at n=42A308930
- Number of compositions of n with weakly increasing first quotients.at n=42A342492
- a(1) = 1, a(2) = 2; for n >= 3, a(n) = (n-1)^3 - a(n-1) - a(n-2).at n=35A361134
- a(n) = Sum_{k=1..n} (-1)^(k-1) * binomial(floor(n/k)+2,3).at n=45A366395