S12 |
12 |
S10 |
10 |
A.-2 011 | B.-2 012 | C.-2 010 | D.-2 013 |
n(n-1) |
2 |
Sn |
n |
(n-1) |
2 |
Sn+1 |
n+1 |
Sn |
n |
d |
2 |
Sn |
n |
d |
2 |
S12 |
12 |
S10 |
10 |
d |
2 |
S12 |
12 |
S10 |
10 |
2012×(2012-1) |
2 |
2012×(2012-1) |
2 |
b1 |
a1 |
b2 |
a2 |
bn |
an |
1 |
2n |
a-b |
m |
500 |
2n |
bn |
an+2 |
1 |
2 |
Sn |
1 |
an•an+1 |
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