77519

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n+1)/3.at n=19A048038
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n+2)/3.at n=19A048071
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n+3)/3.at n=19A048082
• Positions at which powers of 2 occur in A057929. (Or -1 if it does not occur.)at n=25A057931
• G.f. satisfies: A(x) = 1/(1 + x*A(x^7)) and also the continued fraction: 1 + x*A(x^8) = [1; 1/x, 1/x^7, 1/x^49, 1/x^343, ..., 1/x^(7^(n-1)), ...].at n=54A101917
• a(n) = C(n,7)-1.at n=13A124090
• a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3) - 4*a(n-4) + 4*a(n-5) - 4*a(n-6) + 4*a(n-7) - 4*a(n-8) + 4*a(n-9) - 3*a(n-10) + 2*a(n-11) - 3*a(n-12) + 2*a(n-13) for n >= 16, with initial values as shown.at n=27A288511
• a(n) = (n^2 + 1) * (2*n - 1).at n=33A290631
• a(n) = Sum_{d|n} sigma(d)^(n/d).at n=19A344061
• Number of compositions of 7*n-3 into parts 1 and 7.at n=7A373929