OFFSET
0,7
LINKS
Reinhard Zumkeller, Rows n = 0..120 of triangle, flattened
FORMULA
a(n, k)=k*a(n, k+1)+a(n, k+2) for n>k.
EXAMPLE
Triangle starts:
[0] 1;
[1] 0, 1;
[2] 1, 1, 1;
[3] 2, 3, 2, 1;
[4] 7, 10, 7, 3, 1;
[5] 30, 43, 30, 13, 4, 1;
[6] 157, 225, 157, 68, 21, 5, 1;
[7] 972, 1393, 972, 421, 130, 31, 6, 1;
[8] 6961, 9976, 6961, 3015, 931, 222, 43, 7, 1;
PROG
(Haskell)
a062323 n k = a062323_tabl !! n !! k
a062323_row n = a062323_tabl !! n
a062323_tabl = map fst $ iterate f ([1], [0, 1]) where
f (us, vs) = (vs, ws) where
ws = (zipWith (+) (us ++ [0]) (map (* v) vs)) ++ [1]
where v = last (init vs) + 1
-- Reinhard Zumkeller, Mar 05 2013
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Henry Bottomley, Jul 05 2001
STATUS
approved