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 A116339 #9 Jan 28 2024 04:50:29 %S A116339 378,617,708,903,8761,45456,54539,693063,8181812,88235288,327935224, %T A116339 330669332,363636365,418318517,428571430,461538455,538461540, %U A116339 571428565,581681478,636363630,669330663,672064771,691571588 %N A116339 k times k+6 gives the concatenation of two numbers m and m+7. %H A116339 Robert Israel, <a href="/A116339/b116339.txt">Table of n, a(n) for n = 1..8987</a> %p A116339 f:= proc(d) local S,x; %p A116339 S:= map(rhs@op,[msolve((x+3)^2 = 16, 10^d+1)]); %p A116339 end proc: %p A116339 g:= proc(n,d) local m; m:= ((n+3)^2-16)/(10^d+1)+7; m >= 10^(d-1) and m < 10^d end proc: %p A116339 sort([seq](op(select(g,f(i),i)),i=2..13)); # _Robert Israel_, Jan 27 2024 %Y A116339 Cf. A116208, A116325, A116338, A116340, A116345. %K A116339 nonn,base %O A116339 1,1 %A A116339 _Giovanni Resta_, Feb 06 2006