13236
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 30912
- Proper Divisor Sum (Aliquot Sum)
- 17676
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4408
- Möbius Function
- 0
- Radical
- 6618
- Omega Function (Ω)
- 4
- 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
- 45
- 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
- If n < 8 then A058966(n), else n*2^(n - 3) - 2*n - 50.at n=10A058967
- Expansion of e.g.f. exp(4x) * I_0(2x).at n=6A081671
- Numbers n such that n^2048 + 1 is prime (a generalized Fermat prime).at n=6A088361
- Column 4 of A048790.at n=9A094160
- Number of permutations p of 1,2,...,n satisfying |p(i+3)-p(i)|<>5 and |p(j+5)-p(j)|<>3 for all i=1..n-3, j=1..n-5.at n=8A189569
- Number of ways to place n nonattacking composite pieces rook + rider[3,5] on an n X n chessboard.at n=7A189859
- Numbers k such that k^2 + 1 is divisible by precisely four distinct primes where the sum of the largest and the smallest is equal to the sum of the other two.at n=3A192770
- Numbers k such that the sum of the largest and the smallest prime divisor of k^2 + 1 equals the sum of the other distinct prime divisors.at n=8A199924
- Numbers n > 1 such that the sum of the distinct prime divisors of n^2 + 1 that are congruent to 1 mod 8 equals the sum of the distinct prime divisors congruent to 5 mod 8.at n=4A215950
- Numbers n such that n*2^2281 - 1 is prime.at n=9A265504
- Volatile sequence: a(n) = A018227(n)-6.at n=37A271998
- Triangle read by rows, T(n,k) = GegenbauerC(m,-n,-2) where m = k if k<n else 2*n-k, for n>=0 and 0<=k<=2n.at n=42A272867
- 5-untouchable numbers.at n=31A284187
- Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. exp(k*x)*BesselI(0,2*x).at n=61A292627
- a(n) is the number of integer partitions of n for which the Kimberling index is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.at n=54A318177
- Triangle read by rows, T(n, k) = 2^(n - k)*M(n, k, 1/2, 1/2), where M(n, k, x, y) is a generalized Motzkin recurrence. T(n, k) for 0 <= k <= n.at n=48A344557
- a(n) = Sum_{k=0..floor(n/2)} (k+1) * binomial(k,2*(n-2*k)).at n=27A392251