31669

Appears in sequences

• a(0) = 1, a(n) = 1 + 2*3 + 4*5 + 6*7 + ... + (2n)*(2n+1) for n > 0.at n=28A098931
• Products (semiprimes) of two distinct double-safe primes.at n=13A157356
• Smallest number with "natural" logarithm n, cf. A061373.at n=37A182061
• Number of partitions of n such that 2*(greatest part) >= (number of parts).at n=39A237755
• Number of n X 4 binary arrays with rows and columns lexicographically nondecreasing and row and column sums nonincreasing.at n=37A266543
• Number of nX3 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.at n=5A283095
• Number of nX6 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.at n=2A283098
• T(n,k) = Number of n X k 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.at n=30A283100
• T(n,k) = Number of n X k 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements.at n=33A283100
• a(n) = n*(n^3 + 2*n^2 - 5*n + 10)/8.at n=22A294259
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + 2*b(n-1) - b(n-2) - 1, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=18A294564