15168
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 28
- Divisor Sum
- 40640
- Proper Divisor Sum (Aliquot Sum)
- 25472
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4992
- Möbius Function
- 0
- Radical
- 474
- Omega Function (Ω)
- 8
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 40
- 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
- Shifts left two terms under the binomial transform.at n=12A000995
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 61.at n=32A031559
- Number of divisors of n equals the average of distinct prime factors of n.at n=42A067547
- Arithmetic derivative of n!.at n=7A068311
- Coefficient triangle of polynomials (falling powers) related to convolutions of A002605(n), n>=0, (generalized (2,2)-Fibonacci). Companion triangle is A073404.at n=7A073403
- Coefficient triangle of polynomials (rising powers) related to convolutions of A002605(n), n >= 0, (generalized (2,2)-Fibonacci). Companion triangle is A073406.at n=8A073405
- Sum of smallest parts (counted with multiplicity) of all partitions of n into odd parts.at n=43A092313
- a(1)= 10000, a(2)= 10000; for n>2, a(n)= ( a(n-2) + a(n-1) ) (mod 20000).at n=19A096973
- Difference between n-th prime squared and n-th perfect square.at n=30A106588
- Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1),U=(1,2), or d=(1,-1) and have k returns to the x-axis.at n=33A108435
- Number of 1's in all partitions of n with no even parts repeated.at n=32A117276
- A triangular sequence from 2^n times the coefficients of characteristic polynomials of a rational tridiagonal matrix type: M(3)= {{1/2,-1,0} {-1,1/2,-m}, {0,-1,1/2}}};m=-1; polynomial recursion associated is: p(x, n) = (1 - 2*x)*p(x, n - 1)/2 - p(x, n - 2);.at n=58A136330
- Partial sums of A160410.at n=24A160799
- A triangle related to the a(n) formulas for the rows of the ED2 array A167560.at n=48A167565
- The fourth left hand column of triangle A167565.at n=6A167567
- Partial sums of A247666.at n=47A253767
- Number of (7+2) X (n+2) 0..1 arrays with every 3 X 3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=11A254913
- Number of integer partitions of n into relatively prime parts that are all greater than 1.at n=45A302698
- a(n) = 54*n^2 - 26*n + 4 (n>=1).at n=16A304381
- Number of free midpoint-free polycubes of size n, identifying rotations and reflections.at n=15A368029