81000

Appears in sequences

• a(n) = floor(n/5)*floor((n+1)/5)*floor((n+2)/5)*floor((n+3)/5)*floor((n+4)/5).at n=48A008382
• Numbers of form 3^i*10^j, with i, j >= 0.at n=33A025616
• Numbers of form 9^i*10^j, with i, j >= 0.at n=18A025635
• a(n) = 81*10^(n-2), a(0)=1, a(1)=8.at n=5A055996
• Triangle read by rows: T(n,k) is the number of labeled commutative monoids of order n with k idempotents.at n=17A058159
• Numbers n divisible by exactly five nontrivial permutations (rearrangements) of the digits of n.at n=1A090060
• a(n) = n^2 * (n+1)^3.at n=9A099762
• a(n) = 3*n^3.at n=30A117642
• Numbers k such that k and k^2 use only the digits 0, 1, 5, 6 and 8.at n=14A136870
• Numbers whose Spanish names include all five vowels exactly once.at n=4A163321
• Inverse of binomial matrix (10^n,1) A164899. (See A164899 for companion sequence.)at n=33A164915
• Totally multiplicative sequence with a(p) = 3*(p+3) for prime p.at n=39A167322
• Totally multiplicative sequence with a(p) = (p+1)*(p+3) = p^2+4p+3 for prime p.at n=23A167353
• Numbers n such that tau(phi(n)) = sigma(rad(n)).at n=29A173745
• Numbers with prime factorization p^3*q^3*r^4 where p, q, and r are distinct primes.at n=1A190472
• Strong Achilles numbers: Achilles numbers m such that phi(m) is also an Achilles number, where phi(m) denotes Euler's totient function of m.at n=30A194085
• Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..3 2 X n array.at n=17A219715
• Numbers k such that k*sum_of_digits(k) is a perfect cube.at n=20A227227
• Common difference in sets of 3 consecutive palindromic primes (palprimes) in arithmetic progression.at n=18A229781
• Common difference in sets of 3 consecutive palindromic primes (palprimes) in arithmetic progression.at n=14A229781