21287

Appears in sequences

• Number of bracelets (turnover necklaces) of n beads of 2 colors, 7 of them black.at n=21A032280
• Denominators of continued fraction convergents to sqrt(31).at n=11A041051
• Denominators of continued fraction convergents to sqrt(124).at n=13A041225
• Denominators of continued fraction convergents to sqrt(279).at n=11A041525
• T(5,n) with T(n,m) as in A063394.at n=6A063398
• Number of integer sequences [y(1),...,y(n)] such that |y(i)-y(i+1)|<=1, 1=y(1)<=y(i)<=y(n).at n=12A088456
• Numbers k such that binomial(4k, k) - 1 is prime.at n=18A125240
• Number of natural numbers between exponents of successive Mersenne primes.at n=25A157891
• Row sums of triangle defined in A113820.at n=27A160968
• Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 n X 2 array.at n=28A219211
• The y member of the positive proper fundamental solution (x = x2(n), y = y2(n)) of the second class for the Pell equation x^2 - D(n)*y^2 = +8 for even D(n) = A264354(n).at n=4A264439
• a(n) = n^3 + 2*n^2 + 5*n + 11.at n=27A271779
• Number of n X 6 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 3 or 6 neighboring 1s.at n=15A296552
• Consecutive states of the linear congruential pseudo-random number generator 171*s mod 30269 when started at s=1.at n=22A385031