Wednesday, March 22, 2017

Number of the day: 9912

Properties of the number 9912:

9912 = 23 × 3 × 7 × 59 is the 8689th composite number and is not squarefree.
9912 has 4 distinct prime factors, 32 divisors, 19 antidivisors and 2784 totatives.
9912 has a semiprime digit sum 21 in base 10.
9912 has a Fibonacci digit sum 21 in base 10.
9912 has a triangular digit sum 21 in base 10.
Reversing the decimal digits of 9912 results in a semiprime.
9912 = 24792 - 24772 = 12412 - 12372 = 8292 - 8232 = 4192 - 4072 = 3612 - 3472 = 1912 - 1632 = 1392 - 972 = 1012 - 172 is the difference of 2 nonnegative squares in 8 ways.
9912 is the difference of 2 positive pentagonal numbers in 3 ways.
9912 = 202 + 262 + 942 is the sum of 3 positive squares.
99122 is the sum of 3 positive squares.
9912 is a divisor of 8272 - 1.
9912 = '991' + '2' is the concatenation of 2 prime numbers.
9912 is palindromic in (at least) base 39.
9912 in base 38 = 6WW and consists of only the digits '6' and 'W'.
9912 in base 39 = 6K6 and consists of only the digits '6' and 'K'.
9912 in base 44 = 55C and consists of only the digits '5' and 'C'.

The number 9912 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A002597: Number of partitions into one kind of 1's, two kinds of 2's, and three kinds of 3's.
A006967: Number of graceful permutations of length n.
A025231: a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 3.
A047891: Number of planar rooted trees with n nodes and tricolored end nodes.
A049374: A triangle of numbers related to triangle A030527.
A092000: Numbers that can be expressed as the difference of the squares of primes in exactly four distinct ways.
A105720: Triangular matchstick numbers in the class of prime numbers: sum of n-th and next n primes.
A180281: Triangle read by rows: T(n,k) = number of arrangements of n indistinguishable balls in n boxes with the maximum number of balls in any box equal to k.
A235047: Permutation of nonnegative integers: a(n) = A235199(A234840(n+1)-1).
A241648: Numbers m such that the GCD of the x's that satisfy sigma(x)=m is 3.

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