A226555 - OEIS

A226555

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

1, 5, 4, 13, 7, 25, 10, 33, 17, 45, 16, 69, 19, 65, 38, 81, 25, 109, 28, 125, 55, 105, 34, 177, 53, 125, 68, 181, 43, 241, 46, 193, 89, 165, 100, 301, 55, 185, 106, 321, 61, 349, 64, 293, 167, 225, 70, 433, 109, 341, 140, 349, 79, 433, 162, 465, 157, 285, 88

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OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

EXAMPLE

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

. -- -------------------------------------------------------- --------

. 1: 1 1

. 2: 1/2 2 5/2

. 3: 1/3 2/3 3 4

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

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

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

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

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

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

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

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

. 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 .

PROG

(Haskell)

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

a226555 n = numerator $ sum $

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

CROSSREFS

Cf. A040001 (denominators).

Sequence in context: A189235 A019068 A215947 * A147685 A353151 A078930

Adjacent sequences: A226552 A226553 A226554 * A226556 A226557 A226558

KEYWORD

nonn,frac

AUTHOR

Reinhard Zumkeller, Jun 10 2013

STATUS

approved