OFFSET
1,1
COMMENTS
For odd terms, the number of digits in the first "half" is one more than in the second half. Even terms imply the second half begins with 1; odd terms, with 9.
The second-half numbers:
1 1
2 97932384626
3 99375105820974944592..
4 99862803482534211706..
5 99999983729780499510..
6 99999993176688420006..
7 10000000420467135547..
8 99999998414267344764..
9 99999999542282360035..
10 10000000012202360559..
11 99999999941927584272..
12 99999999948261395946..
13 10000000002413899137..
14 99999999975954453917..
15 99999999988383727123..
EXAMPLE
a(1) is 2 because 3/1 (1+1 digits) provides the first approximation to Pi. a(2) is 23 because 314159265358/97932384626 (12+11 digits) provides the next better approximation.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Hans Havermann, Jul 18 2014
EXTENSIONS
a(12)-a(15) from Hans Havermann, Jul 19 2014
STATUS
approved