21883

Appears in sequences

• a(0) = 1, a(1) = 2, a(2) = 5; for n >= 3, a(n) = a(n - 1) - 2*a(n - 2) + a(n - 3).at n=33A121311
• a(n) = 1 + 21 n + 168 n^2 + 588 n^3 + 1029 n^4.at n=2A134155
• Row sums of Riordan array (c(-x^2),xc(-x^2)^2)^(-1) where c(x) is the g.f. of A000108.at n=13A138164
• Number of dispersed Dyck paths of length n (i.e., Motzkin paths of length n with no (1,0) steps at positive heights) having only ascents of even length (an ascent is a maximal sequence of consecutive (1,1)-steps).at n=26A191321
• Last time n appears in the first differences of n*log(n): A217865.at n=9A217866
• Number of partitions p of n such that 2*(number of even numbers in p) < (number of odd numbers in p).at n=47A241651
• Number of (n+2) X (6+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=19A252717
• Number of nX5 0..1 arrays with every element equal to 0, 1, 2, 4, 6 or 8 king-move adjacent elements, with upper left element zero.at n=10A299385
• E.g.f. A(x) satisfies A(x) = 1 + (exp(x) - 1) * A(3*x).at n=4A355088
• Where records occur in A385482.at n=12A385483