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 A059578 #6 Sep 29 2022 15:22:57 %S A059578 1,2,7,30,147,792,4559,27500,171645,1099388,7185101,47724494, %T A059578 321225165,2186177302,15018795171,104011496474,725373340023, %U A059578 5089785834004,35907469451787,254541483884544,1812185157383017,12951828431246472,92893383046741073,668383820775639066 %N A059578 Variation of Boustrophedon transform applied to 1,1,1,1,... Fill an array by diagonals, all in the 'up' direction. The first column is 1,1,1,1,.... For the next element of a diagonal, add to the previous element the elements of the row and the column the new element is in. The first row gives a(n). %e A059578 The array begins %e A059578 1 2 7 30 ... %e A059578 1 4 20 ... %e A059578 1 8 ... %e A059578 1 ... %Y A059578 Cf. A000667, A035002, A059216, A059219, A059502, A059513. %K A059578 easy,nonn %O A059578 1,2 %A A059578 _Floor van Lamoen_, Jan 23 2001 %E A059578 More terms from _Sean A. Irvine_, Sep 29 2022