81901

Properties

Appears in sequences

• a(n) = n*a(n-1) + (n-4)*a(n-2), a(2) = 0, a(3) = 1.at n=7A001909
• Denominators of approximations to e.at n=34A006259
• Number of terms in n-th derivative of a function composed with itself 8 times.at n=10A024208
• Sums of 5 distinct powers of 5.at n=31A038477
• Matrix 8th power of partition triangle A008284.at n=45A050302
• Triangular array formed from successive differences of factorial numbers, then with factorials removed.at n=61A060475
• Table T(n,k) giving number of ways of obtaining exactly 0 correct answers on an (n,k)-matching problem (1 <= k <= n).at n=50A076731
• Primes which can be expressed as sum of distinct powers of 5.at n=16A077719
• a(n) = (1/n!)*A023043(n).at n=4A094795
• Denominators of "Farey fraction" approximations to e.at n=36A119015
• Numbers in A137365 but not in A137366.at n=7A138556
• Apéry-like numbers for the constant e: a(n) = 1/(n-1)!*Sum_{k = 0..n+1} (-1)^k*C(n+1,k)*(2*n-k)! for n >= 1.at n=5A143413
• Square array A(n,k), n>=1, k>=1, read by antidiagonals: A(n,k) = Fibonacci rabbit sequence number n coded in base k.at n=40A144287
• Fibonacci rabbit sequence number n coded in base n, also diagonal of A144287.at n=4A144288
• Primes of the form x^2 + 5*y^2, where x and y=x+1 are consecutive natural numbers.at n=25A176608
• Where A024573 becomes a record.at n=16A182219
• Number of 3 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors.at n=13A208638
• Number of terms in 10th derivative of a function composed with itself n times.at n=7A215628
• Primes whose base-5 representation also is the base-2 representation of a prime.at n=12A235462
• Centered 15-gonal (or pentadecagonal) primes.at n=23A264822