30300

Appears in sequences

• a(n) = floor(n*(n+2)*(2*n-1)/8).at n=48A007518
• Coefficients of ménage hit polynomials.at n=4A058089
• Numbers occurring twice in A068627.at n=25A068628
• Triangle read by rows: T(n,k) = number of ways of seating n couples around a circular table so that exactly k married couples are adjacent (0 <= k <= n).at n=61A094314
• Numbers k such that k and k^2 use only the digits 0, 1, 3, 8 and 9.at n=49A136852
• Triangle T(n, k) = coefficients of p(n,x), where p(n,x) = Sum_{j=0..n} (2*n*(n-j)!/(2*n-j)) * binomial(2*n-j, j) * (x-1)^j and p(0,x) = 1, read by rows.at n=61A156996
• Numbers k which are concatenations k=x//y such that x^2 + y^2 is a multiple of k.at n=24A162463
• Numbers whose decimal expansion contains only 0's and 3's.at n=20A169966
• G.f.: A(x) = Sum_{n>=0} (1 + x)^(n^2+n) / 2^(n+1).at n=4A173218
• Numbers such that each digit is the sum of two or more other digits.at n=10A203591
• G.f.: Sum_{n>=1} (2 - (1-x)^n) * (1 - (1-x)^n)^(n-1) / (1-x)^(n^2).at n=5A220231
• Number of (n+1) X (2+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=3A235252
• Number of (n+1) X (4+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=1A235254
• T(n,k) is the number of (n+1) X (k+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=11A235258
• T(n,k) is the number of (n+1) X (k+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).at n=13A235258
• Number T(n, k) of ways to place k points on an n X n X n triangular grid so that no pair of them has distance sqrt(3). Triangle read by rows.at n=53A244500
• Number of ways to place 4 points on an n X n X n triangular grid so that no pair of them has distance sqrt(3).at n=4A244502
• Number of (n+2) X (5+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically.at n=8A253507
• Sequence A261220 shown in factorial base: a(n) = A007623(A261220(n)).at n=49A260743
• a(n) = n*(n + 1)*(4*n + 5)/2.at n=24A281381