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 A078263 #21 Jun 25 2025 19:53:59
%S A078263 1,252,39483,5332114,670592745,80779853376,9449772114007,
%T A078263 1082152022374638,121932631112635269,135650052221140070110,
%U A078263 1371589685334334871208531,14951973660666886818972704952,161989023197512459256340110001373,1744593949735321085709329564827297794
%N A078263 Product of the forward and reverse concatenations of 1 to n.
%F A078263 a(n) = A000422(n) * A007908(n). - _Sean A. Irvine_, Jun 25 2025
%e A078263 a(3) = 123*321 = 39483.
%p A078263 a:= n-> parse(cat(1+n-i$i=1..n))*parse(cat($1..n)):
%p A078263 seq(a(n), n=1..14); # _Alois P. Heinz_, Jun 25 2025
%t A078263 frc[n_]:=Module[{r1=FromDigits[Flatten[IntegerDigits/@Range[n]]], r2 = FromDigits[ Flatten[ IntegerDigits/@Range[n,1,-1]]]},r1*r2]; Array[ frc, 20] (* _Harvey P. Dale_, Aug 24 2015 *)
%Y A078263 Cf. A000422, A007908, A078264.
%K A078263 base,nonn
%O A078263 1,2
%A A078263 _Amarnath Murthy_, Nov 24 2002
%E A078263 More terms from _Sascha Kurz_, Jan 04 2003
%E A078263 More terms from _Sean A. Irvine_, Jun 25 2025