|
|
A126576
|
|
a(n) = denominator of the sum of reciprocals of the terms in n-th row of triangle A126571.
|
|
1
|
|
|
1, 6, 60, 140, 630, 31416, 34580, 91080, 1093950, 58549260, 6702696, 61910940, 2379795600, 1197892080, 21742542360, 21741799002768, 143830236550, 2559047531040, 38886283310, 333903908520, 24063048428483064
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
EXAMPLE
|
Row 4 of triangle A126571 is (4,7,5,7).
So a(4) is the denominator of 1/4 +1/7 +1/5 + 1/7 = 103/84.
|
|
MATHEMATICA
|
f[m_, n_] := Block[{k = 0, c = n}, While[c > 0, k++; While[GCD[k, m] > 1, k++ ]; c--; ]; k]; Table[Denominator@Sum[1/f[m, n], {m, n}], {n, 22}] (* Ray Chandler, Dec 29 2006 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
frac,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|