83664

Appears in sequences

• Triangle of coefficients in expansion of D^n (sec x) / sec x in powers of tan x.at n=22A008294
• 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=40A104035
• Numbers k such that k and k^2 use only the digits 3, 4, 6, 8 and 9.at n=22A137129
• Triangle read by rows: T(n,k) = value of (d^2n/dx^2n) (tan^(2k)(x)/cos(x)) at the point x = 0.at n=12A151775
• Final terms in rows of triangle A256600.at n=7A256599
• 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=49A350970
• T(n,n-5), where T(*,*) is A350970.at n=4A350973