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A259953
The sum (in nondecreasing order) of the two numbers in an amicable pair.
4
504, 2394, 5544, 10584, 12600, 21600, 26880, 35712, 133920, 138240, 139104, 157248, 168480, 224640, 245520, 262080, 294840, 311040, 348192, 357120, 388800, 399168, 645624, 698544, 749952, 756000, 892800, 955206, 1017792, 1048320, 1270080, 1296000, 1296000, 1315440, 1347840, 1451520, 1522800, 1666560, 1781136, 1879200, 2041200
OFFSET
1,1
COMMENTS
Also the common value of sigma(x) = sigma(y) of the amicable pairs (x < y) ordered by nondecreasing sum (x + y). See A259933.
Duplicates occur, e.g., a(32) = a(33) = 1296000.
Another version of A180164.
First differs from both A161005 and A180164 at a(9).
FORMULA
a(n) = A259933(2n-1) + A259933(2n) = A260086(n) + A260087(n).
EXAMPLE
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A m i c a b l e p a i r Sum
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n A260086(n) + A260087(n) = a(n)
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1 220 284 504
2 1184 1210 2394
3 2620 2924 5544
4 5020 5564 10584
5 6232 6368 12600
6 10744 10856 21600
7 12285 14595 26880
8 17296 18416 35712
9 66928 66992 133920
10 67095 71145 138240
11 63020 76084 139104
12 69615 87633 157248
... ... ... ...
32 609928 686072 1296000
33 643336 652664 1296000
...
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jul 10 2015
STATUS
approved