22839

Appears in sequences

• Number of ordered quadruples of integers from [ 1,n ] with no common factors between triples.at n=29A015635
• Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 6 sites wide.at n=39A058367
• Number of partitions of n such that the least part occurs exactly four times.at n=50A097092
• Ulam's spiral (ESE spoke).at n=38A143855
• Constant term of the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=17A192962
• n * (11*n^2 + 6*n + 1) / 6.at n=23A215646
• Numbers k such that k*floor(2^k/k) + 1 is prime.at n=57A270427
• a(n) = Sum_{k=1..n} sigma(k)*sigma(2*k), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=20A347108
• Expansion of g^2/(1 - x^2*g), where g = 1+x*g^3 is the g.f. of A001764.at n=7A391122