15048
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 46800
- Proper Divisor Sum (Aliquot Sum)
- 31752
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 1254
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 40
- 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
- Number of loopless rooted planar maps with 3 faces and n vertices and no isthmuses. Also a(n)=T(4,n-3), array T as in A049600.at n=41A006416
- a(n) = T(n,n-1), where T is the array in A026148.at n=9A026152
- Eighth column (m=7) of convolution triangle A059594(n,m).at n=7A059596
- a(n) = 11*n^2 + 22*n.at n=35A067705
- Triangle read by rows in which the n-th row contains n lexicographically earliest distinct numbers such that the sum of the (n-1) terms other than the r-th term is divisible by r.at n=77A083796
- Diagonal of A083796.at n=11A083797
- Numbers n such that n^2048 + 1 is prime (a generalized Fermat prime).at n=7A088361
- a(n) = 2*a(n-1) + prime(n) - prime(n-1), a(1)=2, where prime(n) denotes the n-th prime.at n=12A125180
- Partial sum of irregular primes A000928.at n=39A132360
- 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, 1), (-1, 0, 1), (1, 0, -1), (1, 1, 0)}.at n=9A148751
- Number of permutations of 3 indistinguishable copies of 1..n arranged in a circle with exactly 7 adjacent element pairs in decreasing order.at n=1A151595
- a(n+1) -+ a(n) = prime, a(n+1)*a(n) = average of twin prime pairs, a(1)=1, a(2)=6.at n=41A154494
- Number of line segments connecting exactly 7 points in an n X n grid of points.at n=35A177723
- a(n) = 24*p(n) = 24*A000041(n).at n=20A183008
- Expansion of (x^2+1)/(x^4+2*x^3-2*x+1).at n=19A188802
- Floor-Sqrt transform of numbers of A004148 (secondary structures).at n=25A192684
- First differences of 1/p(n), reciprocal of the number p(n) of unrestricted partitions of n (denominator).at n=20A272340
- Sum over all partitions of n of the number of distinct parts i of multiplicity i.at n=40A276428
- Number of twice-partitions of type (Q,P,Q) and weight n.at n=29A279790
- Constant term in the expansion of (Sum_{k=0..n} k*(x^k + x^(-k)))^3.at n=9A303916