18666

Appears in sequences

• Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion.at n=36A051003
• Number of self-avoiding polygons of area n with 2 (self-avoiding polygon) holes on square lattice (not allowing rotations).at n=4A057407
• a(n) = n*(n+1)*(n^2 - 3*n + 6)/4.at n=17A062026
• a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) - a(n-5) with a(0)=0, a(1)=1, a(2)=2, a(3)=3 and a(4)=4.at n=17A135432
• Number of n X 3 binary arrays with all 1's connected and a path of 1's from top row to bottom row.at n=5A163029
• Number of n X 6 binary arrays with all 1s connected and a path of 1s from left column to right column.at n=2A163041
• Number of nonisomorphic graded posets with 0 and non-uniform Hasse graph of rank n, with exactly 2 elements of each rank above 0.at n=9A206947
• Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) is a part of p.at n=42A241735
• Sum of primes between 100*n and 100*n + 99.at n=15A276355
• a(n) = 1*2*3 - 4*5*6 + 7*8*9 - 10*11*12 + 13*14*15 - ... + (up to n).at n=32A319543
• a(n) = 3*2*1 - 6*5*4 + 9*8*7 - 12*11*10 + 15*14*13 - 18*17*16 + ... - (up to the n-th term).at n=32A319886
• Array read by antidiagonals: T(m,n) is the number of m X n binary arrays with all 1's connected and a path of 1's from top row to bottom row.at n=33A359574
• Expansion of 1/((1 - x^2 - x^3)^2 - 4*x^5).at n=19A376723
• First term of the n-th differences of the squarefree numbers. Inverse zero-based binomial transform of A005117.at n=18A377041