17984

Appears in sequences

• From George Gilbert's marks problem: jumping 6 marks at a time (initial positions).at n=23A019995
• a(n)-th prime is the smallest prime containing exactly n 9's.at n=5A037070
• Number of primes less than 10000n.at n=19A038813
• Number of primes less than 100000n.at n=1A038814
• Numbers n such that 105*2^n-1 is prime.at n=35A050578
• Number of 4 X n binary matrices without unit columns up to row and column permutations.at n=10A057223
• E.g.f.: exp(x)/sqrt(1-x^2).at n=8A081919
• a = a(n) is such that the a-th prime p(a) is the least prime with digital sum equal to n, or a(n)=0 if no such prime exists.at n=45A104290
• a(n) equals the (n*(n+1)/2)-th partial sum of the self-convolution 4th power of A010054, which has the g.f.: Sum_{k>=0} x^(k*(k+1)/2).at n=15A109415
• Triangle read by rows: row n gives coefficients of increasing powers of x in characteristic polynomial of the matrix (-1)^n*M_n, where M_n is the tridiagonal matrix defined in the Comments line.at n=47A124037
• Number of hyperforests with n labeled vertices: analog of A134954 when edges of size 1 are allowed (with no two equal edges).at n=5A134956
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (1, -1, 0), (1, -1, 1), (1, 1, 0), (1, 1, 1)}.at n=7A151025
• Positions of zeros in A165597.at n=25A165598
• Magnetic Tower of Hanoi, total number of moves, optimally solving the [NEUTRAL ; NEUTRAL ; NEUTRAL] pre-colored puzzle.at n=10A183118
• Number of nondecreasing arrangements of 4 numbers in -(n+2)..(n+2) with sum zero.at n=39A188212
• Number of 4-element subsets that can be chosen from {1,2,...,4*n} having element sum 8*n+2.at n=22A204468
• Number of nX5 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero.at n=3A231034
• T(n,k)=Number of nXk 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero.at n=31A231037
• Number of 4Xn 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero.at n=4A231040
• Riordan array ((1-2*x)/(1-3*x+x^2), x/(1-3*x+x^2)).at n=47A238731