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 A085180 #19 Jan 16 2024 08:34:28 %S A085180 1,2,3,5,4,6,14,10,7,8,42,28,13,9,11,132,84,37,19,12,15,429,264,112, %T A085180 41,24,16,17,1430,858,354,126,56,27,18,20,4862,2860,1155,402,131,70, %U A085180 33,21,22,16796,9724,3861,1320,422,174,79,36,23,25,58786,33592,13156,4433 %N A085180 Array A(x,y) giving the position of the y-th x in A007001 listed by rising antidiagonals. %C A085180 Read by upwards antidiagonals as A(1,1), A(2,1), A(1,2), A(3,1), A(2,2), A(1,3), etc. %H A085180 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A085180 In A007001 each n occurs for the first time at position Cat(n), thus A(x,1) (the first row) is A000108. %Y A085180 Variant: A085178. %Y A085180 Inverse permutation: A085181. %Y A085180 First row: A000108, second row: A068875 apart from initial terms, first column: A085197, central diagonal: A001453. %K A085180 nonn,tabl %O A085180 1,2 %A A085180 _Antti Karttunen_, Jun 18 2003