21660

Appears in sequences

• a(n) = n^2*(n^2 - 1)/6.at n=19A008911
• Numbers k such that 147*2^k+1 is prime.at n=30A032423
• Number of binary [ n,3 ] codes without 0 columns.at n=32A034344
• a(n) = 15*n^2.at n=38A064761
• Number of ternary squarefree necklaces.at n=38A066297
• Numbers n such that the sum of n's digits times the sum of the factorials of n's digits is equal to n.at n=3A094209
• Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=12.at n=13A135197
• a(n) = (prime(n)^4 - prime(n)^2)/6.at n=7A138421
• One-half of averages of twin prime pairs of A001318.at n=16A154565
• Number of arrangements of n indistinguishable balls in n boxes with the maximum number of balls in any box equal to n-3.at n=15A180293
• Number of nondecreasing arrangements of n+2 numbers in 0..8 with each number being the sum mod 9 of two others.at n=7A183911
• Number of (n+2) X 3 binary arrays avoiding patterns 001 and 101 in rows and columns.at n=16A202195
• Number of (w,x,y) with all terms in {0,...,n} and 2*max(w,x,y) > 3*min(w,x,y).at n=28A213393
• Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.at n=3A221241
• T(n,k)=Number of nXk arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.at n=18A221245
• Number of 4 X n arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.at n=2A221248
• Numbers of alternating permutations where numbers at odd positions and even positions are monotone respectively.at n=20A256644
• a(n) = 10^(prime(n)-1) mod prime(n)^2.at n=40A265012
• Number of 2 X 2 planar subsets in an n X n X n cube.at n=20A270205
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 589", based on the 5-celled von Neumann neighborhood.at n=27A273113