13726
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 20592
- Proper Divisor Sum (Aliquot Sum)
- 6866
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6862
- Möbius Function
- 1
- Radical
- 13726
- Omega Function (Ω)
- 2
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 120
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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 n-node rooted unlabeled trees with out-degree <=2 and exactly 2 edges at the root.at n=16A036657
- a(n) = A055450(n, n-4).at n=8A055454
- Sum array of Catalan numbers (A000108) read by upward antidiagonals.at n=50A106534
- Number of permutations of length n which avoid the patterns 2134, 3421.at n=8A116706
- Number of ways to build a contiguous building with n LEGO blocks of size 1 X 5 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position.at n=3A123792
- Partial sums of round(7^n/10).at n=6A178397
- Number of distinct solutions of Sum_{i=1..2} (x(2i-1)*x(2i)) = 0 (mod n), with x() only in 1..n-1.at n=43A180773
- Number of (n+1)X(n+1) 0..3 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.at n=1A187460
- T(n,k)=Number of (n+1)X(n+1) 0..k arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.at n=7A187462
- Number of 3X3 0..n arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.at n=2A187463
- Expansion of 1 + Sum_{n>=1} (x^(n^2) / Product_{k>=n} (1 - x^k)).at n=35A188216
- G.f.: 1 = Sum_{n>=0} a(n) * x^n * (1 - (2*n+1)*x)^2.at n=5A222080
- Number of (n+1) X (1+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=7A235080
- T(n,k) is the number of (n+1) X (k+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=28A235087
- T(n,k) is the number of (n+1) X (k+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=35A235087
- Total number of congruence subgroups of PSL(2,Z) of genus n.at n=8A258691
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 310", based on the 5-celled von Neumann neighborhood.at n=32A271198
- Triangle A106534 with reversed rows.at n=49A280470
- Partial sums of A294016.at n=38A294017
- Solution of the complementary equation a(n) = a(n-1) + a(n-3) + a(n-4) + b(n-4), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, and (a(n)) and (b(n)) are increasing complementary sequences.at n=18A295754