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 A171075 #4 Jun 01 2025 18:52:41 %S A171075 1,20,190,1226,6878,35962,180080 %N A171075 Total number of balls on lawn in variant of the tennis ball problem (cf. A171074). %C A171075 Apparently equals A051133(n) - A005893(n) after 1st term. %C A171075 Note that A051133 yields the totals of all C(2n, n) ball sets and A005893 and A090288 are the respective totals of impossible combinations given the rules. %D A171075 David Scambler, Just for fun, more tennis balls, Posting to the Sequence Fans Mailing List, Aug 25 2010. %K A171075 nonn %O A171075 1,2 %A A171075 _N. J. A. Sloane_, Sep 06 2010