21070

Appears in sequences

• Graham-Sloane-type lower bound on the size of a ternary (n,3,4) constant-weight code.at n=38A030504
• 7 times heptagonal numbers: a(n) = 7*n*(5*n-3)/2.at n=35A152777
• Number of partitions of n, where the difference between the number of odd parts and the number of even parts is 8.at n=48A240017
• a(n) = Fibonacci(n) + n*Lucas(n).at n=15A258321
• Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size seven are used and the colors are introduced in increasing order.at n=18A327290
• a(n) is the least integer k such that sigma(k)/(d(k)*sopf(k)) = n where d=A000005, sigma=A000203 and sopf=A008472.at n=32A328174
• Triangle read by rows: row n gives coefficients T(n,k), in descending powers of m, of a polynomial Q_n(m) (of degree n - 1) in an expression for the number of subdivisions A(m,n) of a grid with two rows.at n=31A336244
• Square array read by antidiagonals: A(n,k) is the number of ordered solutions (x_1, x_2, ..., x_n) to equation phi(Product_{i=1..n} x_i) = k * Sum_{i=1..n} phi(x_i), or -1 if there are infinitely many solutions, n >= 1, k >= 1.at n=72A336710