21225

Appears in sequences

• Sum of 10 positive 9th powers.at n=14A003399
• Number of fixed properly-3-dimensional polyominoes with n cells.at n=6A006763
• Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 3,2,1,0.at n=4A037798
• Starting positions of strings of three 8's in the decimal expansion of Pi.at n=18A083637
• Least number m such that the number of numbers k <= m with k > spf(k)^n exceeds the number of numbers with k <= spf(k)^n.at n=8A087719
• Number of different n X n symmetric matrices with nonnegative entries summing to 4. Also number of symmetric oriented graphs with 4 arcs on n points.at n=15A139594
• Number of n X n binary matrices, symmetric under 180 degree rotation, with no more than 2 ones in any 2 X 2 subblock.at n=6A141508
• Base-8 Keith numbers.at n=27A188199
• Triangle read by rows: DX(n,d) = number of properly d-dimensional polyominoes with n cells, modulo translations (n>=1, 0 <= d <= n-1).at n=24A195739
• Number of (n+2) X 9 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..1 introduced in row major order.at n=16A204380
• Floor(AGM(n^2, n^3)), where AGM denotes the arithmetic-geometric mean.at n=41A234362
• Number of length 5 0..n arrays least squares fitting to a zero slope straight line, with a single point taken as having zero slope.at n=13A245135
• a(n) = 3*2^n + 3^n + 6.at n=9A254362
• Third partial sums of ninth powers (A001017).at n=2A254643
• The number of fixed polycubes of size n that span n-4 dimensions.at n=3A259015
• Number of 2 X 2 matrices with all elements in {-n,..,0,..,n} with determinant = 2*permanent.at n=25A280343
• a(n) = n! * Sum_{k=0..n} k^(3*n)/k!.at n=3A356688
• Triangle read by rows: T(n,k) = number of partitions of an n X k rectangle into one or more integer-sided rectangles, 1 <= k <= n = 1, 2, 3, ...at n=14A360451
• Number of ASCII letter 'A' bytes that when compressed with zlib generate a new record longest compressed byte stream.at n=36A375585
• Numbers k such that the concatenation of 1, k! and 1 is prime.at n=4A381040