login
Numerators of row sums of the triangular enumeration of rational numbers A226314(n,k) / A054531(n,k), 1 <= k <= n.
3

%I #4 Jun 10 2013 17:31:09

%S 1,5,4,13,7,25,10,33,17,45,16,69,19,65,38,81,25,109,28,125,55,105,34,

%T 177,53,125,68,181,43,241,46,193,89,165,100,301,55,185,106,321,61,349,

%U 64,293,167,225,70,433,109,341,140,349,79,433,162,465,157,285,88

%N Numerators of row sums of the triangular enumeration of rational numbers A226314(n,k) / A054531(n,k), 1 <= k <= n.

%H Reinhard Zumkeller, <a href="/A226555/b226555.txt">Table of n, a(n) for n = 1..1000</a>

%e . n A226314(n,k) / A054531(n,k), 1<=k<=n<=12 row sums

%e . -- -------------------------------------------------------- --------

%e . 1: 1 1

%e . 2: 1/2 2 5/2

%e . 3: 1/3 2/3 3 4

%e . 4: 1/4 3/2 3/4 4 13/2

%e . 5: 1/5 2/5 3/5 4/5 5 7

%e . 6: 1/6 4/3 5/2 5/3 5/6 6 25/2

%e . 7: 1/7 2/7 3/7 4/7 5/7 6/7 7 10

%e . 8: 1/8 5/4 3/8 7/2 5/8 7/4 7/8 8 33/2

%e . 9: 1/9 2/9 7/3 4/9 5/9 8/3 7/9 8/9 9 17

%e . 10: 1/10 6/5 3/10 7/5 9/2 8/5 7/10 9/5 9/10 10 45/2

%e . 11: 1/11 2/11 3/11 4/11 5/11 6/11 7/11 8/11 9/11 10/11 11 16

%e . 12: 1/12 7/6 9/4 10/3 5/12 11/2 7/12 11/3 11/4 11/6 11/12 12 69/2 .

%o (Haskell)

%o import Data.Ratio ((%), numerator); import Data.Function (on)

%o a226555 n = numerator $ sum $

%o zipWith ((%) `on` toInteger) (a226314_row n) (a054531_row n)

%Y Cf. A040001 (denominators).

%K nonn,frac

%O 1,2

%A _Reinhard Zumkeller_, Jun 10 2013