20840

Appears in sequences

• Maximal number of 1432 patterns in a permutation of 1,2,...,n.at n=33A100354
• G.f.: A(x) = Product_{n>=1} [ (1-x)^5*(1 + 5x + 15x^2 +...+ n(n+1)(n+2)(n+3)/4!*x^(n-1)) ].at n=7A129358
• Number of compositions of n such that the cardinality of the set of parts is 2.at n=20A131661
• a(n) = p(n)*p(n+2)-p(n+1), where p(n) is the n-th prime.at n=33A152530
• Number of n X n X n triangular 0..7 arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors.at n=2A214351
• T(n,k)=Number of nXnXn triangular 0..k arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors.at n=38A214352
• Number of 3 X 3 X 3 triangular 0..n arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors.at n=6A214353
• a(n) = nearest integer to sqrt(10^n/log(10^n)).at n=9A221206
• Number of graphs with n nodes that are chordal and do not have a bowtie as a subgraph.at n=11A243797
• T(n,k)=Number of length n+3 0..k arrays with no pair in any consecutive four terms totalling exactly k.at n=37A246479
• Number of length 2+3 0..n arrays with no pair in any consecutive four terms totalling exactly n.at n=7A246481
• Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.at n=13A283887
• Numbers k such that Bernoulli number B_{k} has denominator 13530.at n=12A295587
• a(n) is the number of ways to tile a size n staircase polyomino with staircase polyominoes.at n=5A334617
• a(n) is the smallest number which can be represented as the sum of n distinct nonzero squares in exactly n ways, or 0 if no such number exists.at n=37A350241
• Triangle read by rows: T(n,k) = A(k,n-k), 1 <= k < n, 2 <= n, where A(m,n) is the number of distinct strings consisting of one X, 2*m-1 Y's and 2*n-1 Z's in which the X lies to the right of at least m Y's and at least n Z's.at n=24A351583
• Triangle read by rows: T(n,k) = A(k,n-k), 1 <= k < n, 2 <= n, where A(m,n) is the number of distinct strings consisting of one X, m+n-1 Y's and m+n-1 Z's in which the X lies to the right of at least m Y's and at least m Z's.at n=24A351585
• Triangle read by rows: T(n,k) is the number of non-isomorphic multiset partitions of weight n with k parts and no singletons or vertices that appear only once, 0 <= k <= floor(n/2).at n=59A369287