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 A171076 #4 Jun 01 2025 18:52:57 %S A171076 2,20,188,1222,6872,35954,180070 %N A171076 Total number of balls in room in variant of the tennis ball problem (cf. A171074). %C A171076 Apparently equals A051133(n) - A090288(n-1) after 1st term. %C A171076 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 A171076 David Scambler, Just for fun, more tennis balls, Posting to the Sequence Fans Mailing List, Aug 25 2010. %K A171076 nonn %O A171076 1,1 %A A171076 _N. J. A. Sloane_, Sep 06 2010