13036
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 22820
- Proper Divisor Sum (Aliquot Sum)
- 9784
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6516
- Möbius Function
- 0
- Radical
- 6518
- Omega Function (Ω)
- 3
- 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
- 50
- 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
- Convolution of Catalan numbers and powers of -1.at n=10A032357
- Least k for the Theodorus spiral to complete n revolutions.at n=35A072895
- a(n) = Sum_{k=1..n} -A068341(k+1)*a(n-k), a(0)=1.at n=14A073777
- Triangle T(n,k), read by rows, formed by setting all entries in the zeroth column and in the main diagonal ((n,n) entries) to 1 and defining the rest of the entries by the recursion T(n,k) = T(n-1,k) - T(n,k-1).at n=76A096470
- a(1)=1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = a(k) + Sum_{j=1..2^m} a(j).at n=42A139485
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 1), (0, 1, 1), (1, -1, 1), (1, 0, -1)}.at n=8A149451
- Transform of Fibonacci(n+1) with Hankel transform (-1)^binomial(n+1,2) * Fibonacci(n+1).at n=22A156906
- Eight bishops and one elephant on a 3 X 3 chessboard: a(n)= (3^(n+1)-Jacobsthal(n+1))-(3^n-Jacobsthal(n)), with Jacobsthal=A001045.at n=8A175659
- G.f.: exp( Sum_{n>=1} sigma(n*2^(n-1))*x^n/n ).at n=10A176361
- Triangle of coefficients of polynomials u(n,x) jointly generated with A207609; see the Formula section.at n=50A207608
- Triangle of coefficients of polynomials v(n,x) jointly generated with A210193; see the Formula section.at n=49A210194
- Perimeter (rounded down) of a tetraflake-like fractal after n iterations, a(1) = 1 (see comments).at n=21A235648
- The 360 degree spoke (or ray) of a hexagonal spiral of Ulam.at n=33A244803
- Number of length n+5 0..3 arrays with some three disjoint pairs in each consecutive six terms having the same sum.at n=15A248484
- Triangle read by rows of coefficients of polynomials C_n(x) = Sum_{k=0..n} (2*k)!*(x - 1)^(n-k)/((k + 1)!*k!).at n=55A271453
- Expansion of Product_{k>=2} (1 - x^k)^k.at n=39A298599
- Expansion of Product_{k>=2} (1 + x^Fibonacci(k))/(1 - x^Fibonacci(k)).at n=35A300414
- Numbers k such that 385*2^k+1 is prime.at n=32A322998
- Lower midsequence of the Fibonacci numbers (1,2,3,5,8,...) and Lucas numbers (1,3,4,7,11,...); see Comments.at n=19A355324