6081
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8112
- Proper Divisor Sum (Aliquot Sum)
- 2031
- 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
- 4052
- Möbius Function
- 1
- Radical
- 6081
- 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
- 62
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = floor( n*(n-1)*(n-2)/14 ).at n=45A011896
- Expansion of 1/((1-x) * (1-4*x) * (1-7*x)).at n=4A016223
- Place where n-th 1 occurs in A023125.at n=40A022787
- (d(n)-r(n))/5, where d = A006527 and r is the periodic sequence with fundamental period (4,1,4,0,1).at n=43A026036
- 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 50.at n=40A031548
- a(n)=(s(n)+4)/10, where s(n)=n-th base 10 palindrome that starts with 6.at n=30A043085
- Consider the Diophantine equation x^3 + y^3 = z^3 - 1 (0 < x < y < z) or 'Fermat near misses'. Arrange solutions by increasing values of z. Sequence gives values of z.at n=13A050787
- Numbers n such that 219*2^n-1 is prime.at n=9A050861
- Third row of number array A082105.at n=38A082109
- The O(1) loop model on the square lattice is defined as follows: At every vertex the loop turns to the left or to the right with equal probability, unless the vertex has been visited before, in which case the loop leaves the vertex via the unused edge. Every vertex is visited twice. The probability that a face of the lattice on an n X infinity cylinder is surrounded by one loop is conjectured to be given by a(n)/A_{HT}(n)^2, where A_{HT}(n) is the number of n X n half turn symmetric alternating sign matrices.at n=4A092373
- Number of compositions of n in which the smallest part is equal to the number of parts.at n=41A098133
- Sum of first 2n primes.at n=27A109722
- Galton triangle T(n, k) = T(n-1, k-1) + (3k-2)*T(n-1, k) read by rows.at n=23A111577
- Group the triangular numbers so that the n-th group sum is a multiple of n. 1, (3, 6, 10, 15), (21), (28), (36, 45, 55, 66, 78), (91, 105, 120, 136, 153, 171, 190), ... Sequence contains n-th group sum divided by n.at n=23A114032
- Sum of primes < 2^n.at n=7A130739
- Sum of primes < n^2.at n=16A139562
- Concatenation of even n and odd n-th nonprime.at n=10A155492
- a(n) = 9*n^2 - 3.at n=25A157872
- Semiprimes in A007504 (the sum of first n primes).at n=15A189072
- E.g.f.: exp( Sum_{n>=1} x^(2*n)/(2*A000108(n)) ) = Sum_{n>=0} a(n)*x^(2*n)/(2*n)!, where A000108 is the Catalan numbers.at n=4A193443