This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A226555 #4 Jun 10 2013 17:31:09 %S A226555 1,5,4,13,7,25,10,33,17,45,16,69,19,65,38,81,25,109,28,125,55,105,34, %T A226555 177,53,125,68,181,43,241,46,193,89,165,100,301,55,185,106,321,61,349, %U A226555 64,293,167,225,70,433,109,341,140,349,79,433,162,465,157,285,88 %N A226555 Numerators of row sums of the triangular enumeration of rational numbers A226314(n,k) / A054531(n,k), 1 <= k <= n. %H A226555 Reinhard Zumkeller, <a href="/A226555/b226555.txt">Table of n, a(n) for n = 1..1000</a> %e A226555 . n A226314(n,k) / A054531(n,k), 1<=k<=n<=12 row sums %e A226555 . -- -------------------------------------------------------- -------- %e A226555 . 1: 1 1 %e A226555 . 2: 1/2 2 5/2 %e A226555 . 3: 1/3 2/3 3 4 %e A226555 . 4: 1/4 3/2 3/4 4 13/2 %e A226555 . 5: 1/5 2/5 3/5 4/5 5 7 %e A226555 . 6: 1/6 4/3 5/2 5/3 5/6 6 25/2 %e A226555 . 7: 1/7 2/7 3/7 4/7 5/7 6/7 7 10 %e A226555 . 8: 1/8 5/4 3/8 7/2 5/8 7/4 7/8 8 33/2 %e A226555 . 9: 1/9 2/9 7/3 4/9 5/9 8/3 7/9 8/9 9 17 %e A226555 . 10: 1/10 6/5 3/10 7/5 9/2 8/5 7/10 9/5 9/10 10 45/2 %e A226555 . 11: 1/11 2/11 3/11 4/11 5/11 6/11 7/11 8/11 9/11 10/11 11 16 %e A226555 . 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 A226555 (Haskell) %o A226555 import Data.Ratio ((%), numerator); import Data.Function (on) %o A226555 a226555 n = numerator $ sum $ %o A226555 zipWith ((%) `on` toInteger) (a226314_row n) (a054531_row n) %Y A226555 Cf. A040001 (denominators). %K A226555 nonn,frac %O A226555 1,2 %A A226555 _Reinhard Zumkeller_, Jun 10 2013