23872

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 77.at n=30A031575
• a(n) = T(n,n-2), array T as in A050143.at n=6A050148
• Triangle G(n,k) read by rows: number of order-preserving partial transformations (of an n-element totally ordered set) of waist k (waist(alpha) = max(Im(alpha))).at n=42A111516
• Number of -n..n arrays x(0..3) of 4 elements with zero sum and no two consecutive zero elements.at n=15A199531
• Number of Motzkin n-paths avoiding even-numbered steps that are flat steps.at n=16A214938
• Positions of 2 in sequence A217916.at n=26A217918
• Number of (n+1) X 3 0..1 matrices with each 2 X 2 subblock idempotent.at n=15A224544
• a(1) = 9, a(2) = 44, a(n) = 4*(a(n-1) + a(n-2)) (n >=3).at n=5A228603
• Expansion of a(x^2) / f(-x) in powers of x where a() is a cubic AGM theta function and f() is a Ramanujan theta function.at n=27A261454
• Irregular triangle read by rows: T(n,m) = number of lattice paths of type B^Q terminating at point (n, m).at n=57A291087
• a(n) = A214938(2n).at n=8A291090
• Number of n X n 0..1 arrays with every element unequal to 0, 1, 2, 3 or 7 king-move adjacent elements, with upper left element zero.at n=5A304769
• Number of nX6 0..1 arrays with every element unequal to 0, 1, 2, 3 or 7 king-move adjacent elements, with upper left element zero.at n=5A304773
• a(n) is the sum of the terms of the symmetric square array defined by M(i,j) = prime(i)+i-j for i >= j and M(i,j) = M(j,i) if i < j.at n=20A308731
• Number of strict compositions of n that are neither increasing nor decreasing.at n=28A333149
• Number of partitions of n with rank 4 (the rank of a partition is the largest part minus the number of parts).at n=56A363213