15368
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 30780
- Proper Divisor Sum (Aliquot Sum)
- 15412
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 7168
- Möbius Function
- 0
- Radical
- 3842
- Omega Function (Ω)
- 5
- 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
- 146
- 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
- Numbers k such that k divides the (right) concatenation of all numbers <= k written in base 13 (most significant digit on right, least significant zeros not written).at n=15A061942
- Call two meanders from A005316 equivalent if they differ by a reflection in the Y axis (if n even) or by reflections in the X or Y axes (if n odd). Sequence gives number of inequivalent meanders with n crossings.at n=13A077055
- Call two meanders from A005316 with 2n crossings equivalent if they differ by reflections in the X or Y axes. Sequence gives number of inequivalent meanders.at n=7A078592
- Numbers k such that k^2 divides 15^k-1.at n=24A128395
- a(n) = 961*n^2 - 2*n.at n=3A158410
- G.f. is the polynomial (Product_{k=1..16} (1 - x^(3*k)))/(1-x)^16.at n=5A162636
- Numbers k such that k^3 divides 15^(k^2) - 1.at n=39A177915
- Number of 4-step one space at a time bishop's tours on an n X n board summed over all starting positions.at n=22A187157
- Numbers which, when divided by the sum of their prime factors, give a prime number.at n=42A199013
- L.g.f.: -log(1 - Sum_{n>=1} x^(n*(n+1)/2)) = Sum_{n>=1} a(n)*x^n/n.at n=21A224678
- Partial sums of A247666.at n=49A253767
- Number of (not necessarily maximal) cliques in the n X n king graph.at n=39A295906
- Sequences n*(n+1)*(6*n+1)/2 and n*(n+1)*(7*n+1)/2 interleaved.at n=32A296636
- Number of even parts in the partitions of n into 6 parts.at n=50A309551
- Primitive abundant numbers (A071395) with a record gap to the next primitive abundant number.at n=8A334419
- Numbers k such that A011772(k) > A344878(k) and A011772(k) is a divisor of A344875(k).at n=13A344595
- Triangle read by rows: T(n,k) is the number of chains of length k in the poset of all arithmetic progressions contained in {1,...,n} of length in the range [1..n-1], ordered by inclusion.at n=49A347580
- Coefficients T(n,k) of x^n*y^k in A(x,y) for n >= 0, k = 0..3*n+1, where A(x,y) satisfies: y = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x,y)^((n-1)^2), as an irregular triangle read by rows.at n=72A356500
- Coefficients T(n,k) of x^(4*n+1-k)*y^k in A(x,y) for n >= 0, k = 0..3*n+1, where A(x,y) satisfies: y = Sum_{n=-oo..+oo} (-x)^(n^2) * A(x,y)^((n-1)^2), as an irregular triangle read by rows.at n=55A356501
- a(n) = floor( Sum_{k=0..n-1} n^k / (k! * a(k)) ), for n > 0 with a(0) = 1.at n=17A357549