21090

Appears in sequences

• McKay-Thompson series of class 26B for Monster.at n=32A058597
• Numbers k such that prime(k) +/- k and prime(k) +/- 2k are all primes.at n=5A112530
• Expansion of q^(-1) * (chi(-q^13) / chi(-q))^2 in powers of q where chi() is a Ramanujan theta function.at n=32A128518
• Least number k such that k*p(n)*(k*p(n)+1)-1, k*p(n)*(k*p(n)+1)+1, k*p(n)*(k*p(n)+3)-1 and k*p(n)*(k*p(n)+3)+1 are all primes, two pairs of twin primes, with p(i) = i-th prime.at n=40A139638
• Number of ways to place 2 nonattacking nightriders on an n X n cylindrical board.at n=14A196810
• Number of (w,x,y) with all terms in {0,...,n} and w < range{w,x,y}.at n=36A212967
• Number of partitions of n in which any two parts differ by at most 10.at n=40A218512
• Number of (n+1) X (4+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).at n=4A235306
• Number of (n+1) X (5+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).at n=3A235307
• T(n,k) is the number of (n+1) X (k+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).at n=31A235310
• T(n,k) is the number of (n+1) X (k+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).at n=32A235310
• Number of n X 5 0..2 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 3.at n=30A239358
• Partial sums of A169707.at n=37A253098
• Numbers divisible by prime(d) for each digit d in their base-9 representation, none of which may be zero.at n=50A256879
• Number of simple connected graphs with n nodes rooted at a pair of distinguished vertices.at n=6A304074
• Perimeters of more than one primitive 120-degree integer triangle.at n=13A350047
• Cumulative sums of the first ceiling(n/2)+1 elements of rows 0 to n in Pascal's triangle.at n=14A350851
• Consecutive internal states of the linear congruential pseudo-random number generator (171*s + 11213) mod 53125 when started at 1.at n=23A385039