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A114449
If H(0,n) = 1/n, H(m,n) = sum{k=1...n} H(m-1,k), then a(n) = (2n)!*H(n,2n)/(4n-1).
1
1, 22, 2232, 526256, 223342560, 149004576000, 143638792012800, 188865721926604800, 324805825447366348800, 707653302810219988992000, 1904745046396912124461056000, 6206775274489558456631623680000
OFFSET
1,2
COMMENTS
Every term is an integer.
EXAMPLE
H(2,4) = H(1,1) +H(1,2) +H(1,3) +H(1,4) =
1 + (1 +1/2) + (1 +1/2 +1/3) + (1 +1/2 + 1/3 +1/4) = 77/12.
So a(2) = 24 *(77/12)/7 = 22.
MAPLE
H := proc(m, n) option remember ; if m = 0 then 1/n ; else add( H(m-1, k), k=1..n) ; fi ; end: A114449 := proc(n) (2*n)!*H(n, 2*n)/(4*n-1) ; end: for n from 1 to 20 do printf("%d, ", A114449(n)) ; od: # R. J. Mathar, Jan 30 2008
CROSSREFS
Sequence in context: A253128 A046445 A133235 * A069221 A069222 A117990
KEYWORD
nonn
AUTHOR
Leroy Quet, Feb 14 2006
EXTENSIONS
More terms from Brent A. Yorgey, Jul 27 2007
More terms from R. J. Mathar, Jan 30 2008
STATUS
approved