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 A334745 #32 Apr 12 2023 10:52:32 %S A334745 1,1,1,1,1,1,1,2,1,1,2,1,1,2,2,1,1,2,2,1,1,3,2,3,1,1,3,2,3,1,1,3,3,3, %T A334745 3,1,1,3,3,3,3,1,1,4,3,6,3,4,1,1,4,3,6,3,4,1,1,4,4,6,6,4,4,1,1,4,4,6, %U A334745 6,4,4,1,1,5,4,10,6,10,4,5,1,1,5,4,10,6 %N A334745 Starting with a(1) = a(2) = 1, proceed in a square spiral, computing each term as the sum of diagonally adjacent prior terms. %H A334745 Peter Kagey, <a href="/A334745/b334745.txt">Table of n, a(n) for n = 1..10000</a> %H A334745 Peter Kagey, <a href="/A334745/a334745.png">Bitmap illustrating the parity of the first 2^22 terms</a>. (Even and odd numbers are represented with black and white pixels respectively.) %F A334745 Conjecture: a(2n-1) = A247976(n). %e A334745 Spiral begins: %e A334745 ... 3---3---3---3---1 %e A334745 | %e A334745 1---1---2---2---1 1 %e A334745 | | | %e A334745 2 1---1---1 1 3 %e A334745 | | | | | %e A334745 2 1 1---1 2 2 %e A334745 | | | | %e A334745 1 1---2---1---1 3 %e A334745 | | %e A334745 1---3---2---3---1---1 %e A334745 The last illustrated term above is a(35) = 3 = 2 + 1 because diagonally down-right is 2 and diagonally down-left is 1. %Y A334745 Cf. A141481, A278180, A334741, A334742. %Y A334745 The x- and y-coordinates at n-th step are A174344 and A274923 respectively. %K A334745 nonn %O A334745 1,8 %A A334745 _Alec Jones_ and _Peter Kagey_, May 09 2020