1023120

Appears in sequences

• Triangle of coefficients in expansion of D^n (sec x) / sec x in powers of tan x.at n=27A008294
• E.g.f. satisfies A(x) = 1 + x * A(x / (1 - x)).at n=7A048800
• Triangle T(n,k), 0 <= k <= n, read by rows, defined by T(0,0) = 1; T(0,k) = 0 if k>0 or if k<0; T(n,k) = k*T(n-1,k-1) + (k+1)*T(n-1,k+1).at n=50A104035
• Number of 2 X 2 matrices with entries in {0,1,...,n} and odd determinant with no entry repeated.at n=41A279483
• Triangular array read by rows: T(n,k) is the number of partial functions on [n] with exactly k connected components, n>=0, 0<=k<=n.at n=41A349950
• Triangle T(n,k) (n>=0, 0<=k<=n) read by rows: T(0,0)=T(1,1)=1; T(n,0) is the Euler number A000111(n-1) for n>=1; T(n,n-1) = T(n,n) = (n-2)! for n>=2; interior entries are given by T(n,k) = m*T(n-1,k-1)+(k+1)*T(n-1,k+1) where m = k if n+k is even or k-1 if n+k is odd.at n=60A350970
• T(n,n-5), where T(*,*) is A350970.at n=5A350973
• a(n) = n*(3*n^4 + 15*n^3 + 25*n^2 - 15*n - 28)/60.at n=28A365373