48640

Appears in sequences

• Number of singular 2 X 2 matrices over Z(n) (i.e., with determinant = 0).at n=31A020478
• a(n) = (1/C(n,0) + 1/C(n,1) + ... + 1/C(n,k))*L, where k = [ n/2 ], L = LCM{C(n,0), C(n,1),..., C(n,n)}.at n=15A025534
• House numbers (version 2): a(n) = (n+1)^3 + (n+1)*Sum_{i=0..n} i.at n=31A050509
• a(1) = 4; a(n) = smallest composite number greater than the sum of all previous terms.at n=14A070232
• Number of n X n circulant invertible (0,1) matrices over the reals.at n=15A086323
• a(n) = (3*8^n-4^n)/2.at n=5A165148
• a(n) = 2^(floor(n/2))+2^(floor(n/2)-1)-2^(floor((n-1)/3)).at n=28A170831
• Number of (n+1) X (3+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=20A250724
• 100-gonal numbers: a(n) = 98*n*(n-1)/2 + n.at n=32A261276
• Integers with precisely eight partitions into sums of four squares of nonnegative numbers.at n=43A294309
• Irregular triangle T(n,k) read by rows in which n-th row lists in colex order all series-reduced tree degree sequences D of n nodes encoded as t = Product_{d in D} prime(d); n >= 4, 1 <= k <= A002865(n-2).at n=22A345970
• a(n) is the number of elements z of Z_p[i] such that #{z^k, k >= 0} = p^2-1 (where p denotes A002145(n), the n-th prime number congruent to 3 modulo 4).at n=39A374001
• Numbers k such that k + A224787(k) is a square.at n=23A386640
• a(n) = Sum_{k=0..floor(n/2)} binomial(k+1,4*n-8*k+1).at n=36A390221
• a(n) = Sum_{k=0..floor(3*n/8)} binomial(k,3*n-8*k).at n=51A392272