This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A256550 Triangle read by rows, T(n,k) = EL(n,k)/(n-k+1)! and EL(n,k) the matrix-exponential of the unsigned Lah numbers scaled by exp(-1), for n>=0 and 0<=k<=n. 1
 1, 0, 1, 0, 1, 1, 0, 2, 3, 1, 0, 5, 12, 6, 1, 0, 15, 50, 40, 10, 1, 0, 52, 225, 250, 100, 15, 1, 0, 203, 1092, 1575, 875, 210, 21, 1, 0, 877, 5684, 10192, 7350, 2450, 392, 28, 1, 0, 4140, 31572, 68208, 61152, 26460, 5880, 672, 36, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS FORMULA T(n+1,1) = Bell(n) = A000110(n). T(n+2,2) = C(n+2,2)*Bell(n) = A105479(n+2). T(n+1,n) = A000217(n). T(n+2,n) = A008911(n+1). EXAMPLE Triangle starts: 1; 0,    1; 0,    1,    1; 0,    2,    3,    1; 0,    5,   12,    6,    1; 0,   15,   50,   40,   10,    1; 0,   52,  225,  250,  100,   15,   1; 0,  203, 1092, 1575,  875,  210,  21,  1; PROG (Sage) def T(dim) :     M = matrix(ZZ, dim)     for n in range(dim) :         M[n, n] = 1         for k in range(n) :             M[n, k] = (k*n*gamma(n)^2)/(gamma(k+1)^2*gamma(n-k+1))     E = M.exp()/exp(1)     for n in range(dim) :         for k in range(n) :             M[n, k] = E[n, k]/factorial(n-k+1)     return M T(8) # Computes the sequence as a lower triangular matrix. CROSSREFS Cf. A000110, A000217, A008911, A105479, A256551 (matrix inverse). Sequence in context: A172380 A144633 A264428 * A005210 A264430 A264433 Adjacent sequences:  A256547 A256548 A256549 * A256551 A256552 A256553 KEYWORD nonn,tabl,easy AUTHOR Peter Luschny, Apr 01 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 21 01:18 EDT 2019. Contains 321356 sequences. (Running on oeis4.)