Thursday, April 6, 2017

Number of the day: 7467

Properties of the number 7467:

7467 = 3 × 19 × 131 is a sphenic number and squarefree.
7467 has 3 distinct prime factors, 8 divisors, 15 antidivisors and 4680 totatives.
7467 has a triangular digit product 1176 in base 10.
Reversing the decimal digits of 7467 results in a semiprime.
7467 = (18 × 19)/2 + … + (36 × 37)/2 is the sum of at least 2 consecutive triangular numbers in 1 way.
7467 = 37342 - 37332 = 12462 - 12432 = 2062 - 1872 = 942 - 372 is the difference of 2 nonnegative squares in 4 ways.
7467 is the difference of 2 positive pentagonal numbers in 1 way.
7467 = 12 + 352 + 792 is the sum of 3 positive squares.
74672 is the sum of 3 positive squares.
7467 is a divisor of 7876 - 1.
7467 = '7' + '467' is the concatenation of 2 prime numbers.
7467 is palindromic in (at least) the following bases: -23, and -41.
7467 in base 22 = f99 and consists of only the digits '9' and 'f'.
7467 in base 30 = 88r and consists of only the digits '8' and 'r'.

The number 7467 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A031583: Numbers n such that continued fraction for sqrt(n) has even period and central term 85.
A032279: Number of bracelets (turn over necklaces) of n beads of 2 colors, 5 of them black.
A043589: Numbers n such that base 3 representation has exactly 9 runs.
A074341: a(1) = 4; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.
A076425: Numbers n such that zero is never reached by iterating the mapping k -> abs(reverse(lpd(k))-reverse(gpf(k))). lpd(k) is the largest proper divisor and gpf(k) is the largest prime factor of k.
A083752: Minimal k > n such that (4k+3n)(4n+3k) is a square.
A102724: Sum of the first n pairs of consecutive primes (for example, a(3) = (2+3) + (3+5) + (5+7) = 25).
A220305: Majority value maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to at least half of their horizontal, vertical and antidiagonal neighbors in a random 0..1 nX3 array
A220308: T(n,k)=Majority value maps: number of nXk binary arrays indicating the locations of corresponding elements equal to at least half of their horizontal, vertical and antidiagonal neighbors in a random 0..1 nXk array
A272038: Somos's sequence {b(9,n)} defined in comment in A078495: a(0)=a(1)=...=a(20)=1; for n>=21, a(n)=(a(n-1)*a(n-20)+a(n-10)*a(n-11))/a(n-21).

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