18808

Appears in sequences

• Least term in period of continued fraction for sqrt(n) is 7.at n=27A031431
• n! has a palindromic prime number of digits.at n=27A035067
• Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 5 sites wide.at n=34A058368
• Number of n X n binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=5A266463
• Number of nX6 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=5A266468
• T(n,k) = number of n X k binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=60A266470
• Number of 6Xn binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=5A266473
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 363", based on the 5-celled von Neumann neighborhood.at n=30A268154
• Numbers k such that (86*10^k - 221)/9 is prime.at n=21A288823
• Number of maximal independent vertex sets (and minimal vertex covers) in the n-wheel graph.at n=32A290612
• E.g.f.: exp( Sum_{n>=1} ( Product_{k=1..n} sigma(k) ) * x^n/n! ).at n=6A294343
• Numbers k which are the product of a cube greater than 1 and a prime, and where k-1 and k-2 are semiprimes.at n=33A350284
• a(n) = 7*a(n-1) + 2*7^n - 1, a(0) = 0.at n=4A392138