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 A049634 #8 Aug 06 2021 04:53:00 %S A049634 2,6,9,15,19,29,35,47,55,71,79,101,111,131,145,169,183,217,231,261, %T A049634 279,313,331,373,393,431,455,501,521,579,603,653,685,729,757,817,847, %U A049634 907,941,1005,1033,1115,1147,1213,1255,1325,1363,1451,1487,1561,1605,1689 %N A049634 a(n) = T(n,n+2), array T as in A049627. %o A049634 (PARI) T(n,k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i,j)>1)); \\ A049627 %o A049634 a(n) = T(n, n+2); \\ _Michel Marcus_, Aug 06 2021 %Y A049634 Cf. A049627. %K A049634 nonn %O A049634 0,1 %A A049634 _Clark Kimberling_ %E A049634 More terms from _Sean A. Irvine_, Aug 05 2021