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 A071761 #8 Jul 01 2025 16:03:10 %S A071761 0,1,2,21,31,32,321,421,431,432,4321,5321,5421,5431,5432,54321,64321, %T A071761 65321,65421,65431,65432,654321,754321,764321,765321,765421,765431, %U A071761 765432,7654321,8654321,8754321,8764321,8765321,8765421,8765431,8765432 %N A071761 Dealing cards in a game of solitaire. %C A071761 An infinite square array, %C A071761 a11 a12 a13 ... %C A071761 a21 a22 a23 ... %C A071761 a31 a32 a33 ... %C A071761 a41 a42 a43 ... %C A071761 ............... %C A071761 is built up by antidiagonals: a11 a21 a12 a31 a22 a13 ... The terms of the sequence record the number of entries in each column at each step, e.g. when dealing cards in a game of solitaire. %Y A071761 The parity of this sequence gives A023532. %Y A071761 Cf. A071762, A074909. %K A071761 nonn,easy,nice %O A071761 0,3 %A A071761 _Allan C. Wechsler_, Jun 07 2002 %E A071761 Entry revised by _Jeremy Gardiner_, Dec 08 2004