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 A049632 #13 Aug 06 2021 04:53:37 %S A049632 1,4,6,10,14,22,26,38,46,58,66,86,94,118,130,146,162,194,206,242,258, %T A049632 282,302,346,362,402,426,462,486,542,558,618,650,690,722,770,794,866, %U A049632 902,950,982,1062,1086,1170,1210,1258,1302,1394,1426,1510,1550,1614,1662 %N A049632 a(n) = T(n,n), array T as in A049627. %F A049632 a(n) = 2*A005728(n) if n>=1. - _R. J. Mathar_, Feb 05 2008 %o A049632 (PARI) T(n,k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i,j)>1)); \\ A049627 %o A049632 a(n) = T(n, n); \\ _Michel Marcus_, Aug 06 2021 %Y A049632 Cf. A049627, A049643, A005728. %K A049632 nonn %O A049632 0,2 %A A049632 _Clark Kimberling_ %E A049632 More terms from _Sean A. Irvine_, Aug 05 2021