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 A245331 #9 Jul 22 2014 10:27:34 %S A245331 2,23,87,157,1523,3445551,26620870,30512347,72713283,344661698, %T A245331 1129330411,3886591581,5085084202,11916345303,15510679381 %N A245331 Number of truncated Pi decimal digits that yield record approximations to Pi when the concatenation of the first half of the digits is divided by the second half. %C A245331 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. %C A245331 The second-half numbers: %C A245331 1 1 %C A245331 2 97932384626 %C A245331 3 99375105820974944592.. %C A245331 4 99862803482534211706.. %C A245331 5 99999983729780499510.. %C A245331 6 99999993176688420006.. %C A245331 7 10000000420467135547.. %C A245331 8 99999998414267344764.. %C A245331 9 99999999542282360035.. %C A245331 10 10000000012202360559.. %C A245331 11 99999999941927584272.. %C A245331 12 99999999948261395946.. %C A245331 13 10000000002413899137.. %C A245331 14 99999999975954453917.. %C A245331 15 99999999988383727123.. %e A245331 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. %Y A245331 Cf. A000796, A048940, A193940. %K A245331 nonn,base %O A245331 1,1 %A A245331 _Eric Angelini_ and _Hans Havermann_, Jul 18 2014 %E A245331 a(12)-a(15) from _Hans Havermann_, Jul 19 2014