18486

Appears in sequences

• Numbers n such that n and n+1 are differences between 2 positive cubes in at least one way.at n=18A038594
• Solution to the Dancing School Problem with 4 girls and n+4 boys: f(4,n).at n=12A079909
• Numbers k such that the three second-degree cyclotomic polynomials x^2 + 1, x^2 - x + 1 and x^2 + x + 1 are simultaneously prime when evaluated at x=k.at n=15A087277
• a(n) = n*A002088(n).at n=38A143270
• Number of ways to place 2 nonattacking knights on an n X n board.at n=13A172132
• Number of nX3 0..5 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=9A201137
• Number of intersections of diagonals in the exterior of a regular n-gon.at n=23A211382
• Number of n X 4 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 n X 4 array.at n=6A219682
• T(n,k)=Number of nXk arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nXk array.at n=51A219686
• Number of 7Xn arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 7Xn array.at n=3A219691
• Numbers k such that k^2 +- k +- 1 is prime for all four possibilities.at n=9A236056
• Number of partitions p of n not including ceiling(mean(p)) as a part.at n=40A241337
• a(n) = n*(3*n^2 + 3*n + 1).at n=18A249354
• E.g.f.: A(x,y) = exp(y)*P(x) - Q(x,y), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x,y) = Sum_{n>=1} y^n / Product_{k=1..n} (k - x^k).at n=49A249480
• Number of ways to write n as an ordered sum of 6 prime power palindromes (A084092).at n=40A282845
• Numbers equal to the sum of three oblong numbers in arithmetic progression.at n=40A292314
• G.f.: Sum_{k>=0} x^(2^k) / Product_{j=1..2^k} (1 - x^j).at n=48A339447
• Number of ways to write n as an ordered sum of 6 prime powers (including 1).at n=19A341135