18754

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 11.at n=19A031599
• Numbers m such that sigma(m+1)+sigma(m-1) = 6*phi(m).at n=15A067243
• Numbers k such that phi(k) divides (sigma(k+1) + sigma(k-1)).at n=45A067244
• Expansion of x*(-1+5*x-6*x^2+x^3) / ( (2*x-1)*(x^3-3*x^2+1) ).at n=18A122167
• Triangle T, read by rows, where column k of T = column 0 of T^(k+1) for k>0, with column 0 of T = column 0 of T^3 shift right.at n=39A135902
• Column 3 of triangle A135902.at n=5A135905
• Numbers n such that prime[(n + 1)^2] - prime[n^2] is a perfect square.at n=25A145290
• 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, -1, 0), (-1, -1, 1), (0, 0, 1), (0, 1, 1), (1, 1, -1)}.at n=8A150152
• Number of trailing zeros in sequence of factorials of Fibonacci numbers.at n=24A165753
• 1/16 the number of (n+1) X 4 0..3 arrays with all 2 X 2 subblocks having the same four values.at n=11A184033
• Beach-Williams Pell numbers of type 2p (p prime).at n=15A212074
• Number of partitions p of n such that (sum of parts with multiplicity 1) < (sum of all other parts).at n=40A240448
• Number of length n arrays of permutations of 0..n-1 with each element moved by -5 to 5 places and the total absolute value of displacements not greater than 2*(n-1).at n=8A263902
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 419", based on the 5-celled von Neumann neighborhood.at n=30A272047
• Number of n X 4 0..2 arrays with every element equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.at n=4A277655
• Number of nX5 0..2 arrays with every element equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.at n=3A277656
• T(n,k)=Number of nXk 0..2 arrays with every element equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.at n=31A277659
• T(n,k)=Number of nXk 0..2 arrays with every element equal to some element at offset (-1,0) (-1,1) (0,-1) (0,1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.at n=32A277659
• Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=5A320397
• Number of nX6 0..1 arrays with every element unequal to 0, 1, 2, 3 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=2A320400