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 A077192 #16 May 09 2025 19:57:53
%S A077192 8,90,92,98,992,998,9992,9998,99992,99998,999992,999994,999998,
%T A077192 9999992,9999998,99999992,99999998,999999992,999999998,9999999992,
%U A077192 9999999998,99999999992,99999999998,999999999992,999999999994,999999999998,9999999999992
%N A077192 {Concatenation of n-1 and n+1}/n where n is a member of A069871.
%e A077192 8 and 90 are members since 24/3 = 8, 810/9 = 90.
%e A077192 999994 is in sequence because 999994 = 142856142858/142857 and 142857 is a member of A069871.
%Y A077192 Cf. A069871.
%K A077192 nonn,base
%O A077192 1,1
%A A077192 _Amarnath Murthy_, Nov 01 2002
%E A077192 More terms from _Sascha Kurz_, Feb 10 2003
%E A077192 Inserted missing terms a(12) and a(25) by _Paolo P. Lava_, Nov 05 2014
%E A077192 Offset changed by _Sean A. Irvine_, May 09 2025