21153

Appears in sequences

• T(2n-1,n), where T is the array defined in A025564.at n=6A025569
• a(n) = T(n,[ n/2 ]+1), where T is the array defined in A025564.at n=11A025576
• Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 3,2,0,1.at n=4A037791
• Matrix cube of triangle A104980.at n=22A104990
• Numbers n with property that for each single digit d of n, we can also see the decimal expansion of the d-th prime as a substring of n. Also n may not contain any zero digits.at n=7A135015
• Number of n X 2 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..2 n X 2 array.at n=25A219846
• a(n) is the number of labeled rooted unordered binary trees T where the nodes are labeled with distinct positive integers, the root has label n, each parent label equals the sum of its children labels, and T cannot be extended.at n=31A348850