OFFSET
0,2
COMMENTS
Equals the matrix square of A088956 when treated as a lower triangular matrix. The 2nd hyperbinomial transform of a sequence {b} is defined to be the sequence {d} given by d(n) = sum(k=0..n, T(n,k)*b(k)), where T(n,k) = 2*(n-k+2)^(n-k-1)*C(n,k). Given a table in which the n-th row is the n-th binomial transform of the first row, then the 2nd hyperbinomial transform of any diagonal results in the diagonal located 2 diagonals lower in the table.
LINKS
G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened
FORMULA
T(n, k) = 2*(n-k+2)^(n-k-1)*C(n, k).
E.g.f.: exp(x*y)*(-LambertW(-y)/y)^2.
Note: (-LambertW(-y)/y)^2 = sum(n>=0, 2*(n+2)^(n-1)*y^n/n!).
EXAMPLE
Rows begin:
{1},
{2,1},
{8,4,1},
{50,24,6,1},
{432,200,48,8,1},
{4802,2160,500,80,10,1},
{65536,28812,6480,1000,120,12,1},
{1062882,458752,100842,15120,1750,168,14,1},..
MATHEMATICA
Join[{1}, Table[Binomial[n, k]*2*(n - k + 2)^(n - k - 1), {n, 1, 49}, {k, 0, n}]] // Flatten (* G. C. Greubel, Nov 18 2017 *)
PROG
(PARI) for(n=0, 10, for(k=0, n, print1(2*(n-k+2)^(n-k-1)*binomial(n, k), ", "))) \\ G. C. Greubel, Nov 18 2017
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Paul D. Hanna, Nov 05 2003
STATUS
approved