31493

Appears in sequences

• a(n) = (1/24)*n*(n + 5)*(n^2 + n + 6).at n=27A051743
• Triangle read by rows: T(n,k) is the number of permutations of [n] with exactly k increasing runs of even length.at n=29A097592
• a(n)= a(n-1) +3*a(n-2) -3*a(n-4).at n=16A107384
• a(n) = 14 + floor( (1 + Sum_{j=0..n-1} a(j)) / 2).at n=19A120141
• Number of 1-2-3-4-5 trees with n edges and with thinning limbs. A 1-2-3-4-5 tree is an ordered tree with vertices of outdegree at most 5. A rooted tree with thinning limbs is such that if a node has k children, all its children have at most k children.at n=12A124500
• Number of (n+2)X(4+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=13A254903
• Number of (n+1)X(3+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,1 -1,2 1,0 or 0,-1.at n=9A264545
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 211", based on the 5-celled von Neumann neighborhood.at n=35A270899
• Numbers k such that (188*10^k + 7)/3 is prime.at n=18A295386
• Number of permutations of [n] with exactly floor(n/2) increasing runs of length two.at n=9A317139
• Number of permutations of [2n+1] with exactly n increasing runs of length two.at n=4A317140
• Number of permutations of [n] with exactly four increasing runs of even length.at n=1A317284
• a(n) is the largest k such that the sum of k consecutive reciprocals 1/p_n + ... + 1/p_(n+k-1) does not exceed 1 (where p_n = n-th prime).at n=26A327600
• Positive numbers k such that -k, -(k + 1), -(k + 2), and -(k + 3) are 4 consecutive negative negabinary-Niven numbers (A331728).at n=13A331825
• Numbers m such that there exist positive integers i <= m and j >= m such that m = Sum_{k=i..j} A001065(k), where A001065(k) = sum of the proper divisors of k, and i and j do not both equal m.at n=23A346140
• Number of subsets of {1..n} containing n and some element equal to the sum of two distinct others.at n=16A364756