Monday, November 21, 2016

Number of the day: 4894

Properties of the number 4894:

4894 = 2 × 2447 is semiprime and squarefree.
4894 has 2 distinct prime factors, 4 divisors, 7 antidivisors and 2446 totatives.
4894 has a semiprime digit sum 25 in base 10.
4894 is the sum of 2 positive triangular numbers.
4894 is the difference of 2 positive pentagonal numbers in 2 ways.
4894 = 232 + 422 + 512 is the sum of 3 positive squares.
48942 is the sum of 3 positive squares.
4894 is a divisor of 31223 - 1.
4894 = '489' + '4' is the concatenation of 2 semiprime numbers.
4894 is an emirpimes in (at least) the following bases: 2, 3, 4, 5, 8, 14, 19, 29, 31, 33, 34, 36, 41, 43, 47, 48, 49, 50, 52, 61, 62, 64, 68, 71, 78, 84, 85, 89, 91, and 99.
4894 is palindromic in (at least) the following bases: 22, -18, and -27.
4894 in base 17 = gff and consists of only the digits 'f' and 'g'.
4894 in base 22 = a2a and consists of only the digits '2' and 'a'.
4894 in base 26 = 766 and consists of only the digits '6' and '7'.
4894 in base 28 = 66m and consists of only the digits '6' and 'm'.

The number 4894 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A006227: Number of n-dimensional space groups (including enantiomorphs).
A014126: Number of partitions of 2*n into at most 4 parts.
A021664: Expansion of 1/((1-x)(1-3x)(1-8x)(1-11x)).
A089508: Solution to a binomial problem together with companion sequence A081016(n-1).
A111569: a(n) = a(n-1) + a(n-3) + a(n-4) for n>3, a(0) = -1, a(1) = 1, a(2) = 2, a(3) = 1.
A119996: Numerator of sum(k=1..n, 1 / ( Fibonacci(k) * Fibonacci(k+2) ) ).
A178314: Numbers n with property that n^2 contains "123" as a substring.
A236242: Numbers m with C(2*m, m) + prime(m) prime, where C(2*m, m) = (2*m)!/(m!)^2.
A238340: Number of partitions of 4n into 4 parts.
A251326: T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with every 2X2 subblock having one or two 1s

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