8212
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 14378
- Proper Divisor Sum (Aliquot Sum)
- 6166
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4104
- Möbius Function
- 0
- Radical
- 4106
- 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
- 39
- 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
- a(n) = floor( n*(n-1)*(n-2)/25 ).at n=60A011907
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 60 ones.at n=16A031828
- Starting from generation 6 add previous and next term yielding generation 7.at n=31A048453
- Define C(n) by the recursion C(0) = 4*i where i^2 = -1, C(n+1) = 1/(1 + C(n)), then a(n) = 4*(-1)^n/Im(C(n)) where Im(z) denotes the imaginary part of z.at n=8A069961
- Diagonal of triangular spiral in A051682.at n=42A081268
- Triangle T(n, k) read by rows; given by [0, 1, 0, 2, 0, 3, 0, 4, ...] DELTA [1, 0, 2, 0, 2, 0, 3, 0, 2, 0, 4, 0, 2, 0, ...] (A000005 interspersed with 0's) where DELTA is Deléham's operator defined in A084938.at n=52A085852
- Triangle read by rows: T(n,k) is the number of hill-free Schroeder paths of length 2n that have k weak ascents (1<=k<=n-1 for n>=2; k=1 for n=1). A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1. A weak ascent in a Schroeder path is a maximal sequence of consecutive U and H steps.at n=30A114691
- 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, -1, 1), (-1, 1, 0), (0, 0, -1), (0, 1, 0), (1, 0, 0)}.at n=8A149935
- 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, -1, -1), (-1, 0, 0), (-1, 0, 1), (1, 0, 1), (1, 1, 0)}.at n=7A150696
- a(n) = a(n-1) + 16*a(n-2), starting a(0)=1, a(1)=4.at n=6A158608
- Number of different fixed (possibly) disconnected trominoes bounded tightly by an n X n square.at n=37A163433
- Lexicographically earliest infinite sequence such that (a(i)-a(j)) mod (a(k)-a(j)) is nonzero whenever i,j,k are disjoint.at n=15A178850
- Non-crossing, non-nesting, 7-colored set partitions.at n=4A225033
- Minimum even value unattainable as the sum of 6 attained values of i*(i-1) with i in 0..n.at n=39A225292
- Number of 3 X n 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=28A229446
- a(n) = 9*n^3/2 - 21*n^2/2 + 8*n - 4.at n=11A232495
- Number of partitions of n such that 2*(least part) < greatest part.at n=31A237820
- Number of compositions of n in which the maximal multiplicity of parts equals 2.at n=16A243119
- Number of length n+5 0..1 arrays with at most one downstep in every n consecutive neighbor pairs.at n=29A255996
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 555", based on the 5-celled von Neumann neighborhood.at n=19A272922