20306

Appears in sequences

• Gaussian binomial coefficient [ n,2 ] for q=5.at n=3A006111
• Gaussian binomial coefficient [ n,3 ] for q = 5.at n=2A006112
• Gaussian binomial coefficient [ n,n/2 ] for q=5.at n=5A006115
• Triangle of Gaussian binomial coefficients [ n,k ] for q = 5.at n=17A022169
• Triangle of Gaussian binomial coefficients [ n,k ] for q = 5.at n=18A022169
• Number of sublattices of index n in generic 4-dimensional lattice.at n=24A038991
• T(n,n-2), array T as in A047089.at n=8A047093
• Larger members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b).at n=39A054572
• Areas of a sequence of right-angled figures described below.at n=20A058195
• a(n) = 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=3.at n=24A068020
• Deficient oblong numbers.at n=23A077804
• Multiples of 11 with digit sum 11, with no zero digits in odd places.at n=19A083512
• Triangle T(n, k, q) = ((1-q)/(1-q^k))*c(n-1, q)*c(n, q)/(c(k-1,q)^2*c(n-k,q)*c(n-k+1, q)), where c(n, q) = Product_{j=1..n} (1-q^j) and q = 5, read by rows.at n=11A172302
• Triangle T(n, k, q) = ((1-q)/(1-q^k))*c(n-1, q)*c(n, q)/(c(k-1,q)^2*c(n-k,q)*c(n-k+1, q)), where c(n, q) = Product_{j=1..n} (1-q^j) and q = 5, read by rows.at n=13A172302
• a(n) = 25*n^2 + 25*n + 6.at n=28A177059
• Number of compositions of n such that the number of parts and the greatest part are coprime.at n=15A199886
• a(n) = binomial(n^2,3)/(2*n).at n=11A201106
• a(n) = (4*n+3)*(4*n+2).at n=35A256833
• Numbers with digit sum 11 that are multiples of 11.at n=28A283742
• Irregular triangle read by rows: T(n, k) is the q-multinomial coefficient defined by the k-th partition of n in Abramowitz-Stegun order, evaluated at q = 5.at n=13A347488