21435888

Appears in sequences

• a(n) = (11^(n+1) - 1)/10.at n=7A016123
• Number of sublattices of index n in generic 8-dimensional lattice.at n=10A038995
• a(n) = n^7 + n^6 + n^5 + n^4 + n^3 + n^2 + n + 1.at n=11A053717
• Z(S_m; sigma[1](n), sigma[2](n),..., sigma[m](n)) where Z(S_m; x_1,x_2,...,x_m) is the cycle index of the symmetric group S_m and sigma[k](n) is the sum of k-th powers of divisors of n; m=7.at n=10A068024
• a(n) = Sum_{d|n} Moebius(n/d)*d^(b-1)/phi(n) for b = 9.at n=10A160908