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 A049633 #9 Aug 06 2021 04:53:55 %S A049633 2,5,8,12,18,24,32,42,52,62,76,90,106,124,138,154,178,200,224,250,270, %T A049633 292,324,354,382,414,444,474,514,550,588,634,670,706,746,782,830,884, %U A049633 926,966,1022,1074,1128,1190,1234,1280,1348,1410,1468,1530,1582,1638 %N A049633 a(n) = T(n,n+1), array T as in A049627. %o A049633 (PARI) T(n,k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i,j)>1)); \\ A049627 %o A049633 a(n) = T(n, n+1); \\ _Michel Marcus_, Aug 06 2021 %Y A049633 Cf. A049627. %K A049633 nonn %O A049633 0,1 %A A049633 _Clark Kimberling_ %E A049633 More terms from _Sean A. Irvine_, Aug 05 2021