A078263 Product of the forward and reverse concatenations of 1 to n.

1, 252, 39483, 5332114, 670592745, 80779853376, 9449772114007, 1082152022374638, 121932631112635269, 135650052221140070110, 1371589685334334871208531, 14951973660666886818972704952

Offset

1,2

Links

Table of n, a(n) for n=1..12.

Example

a(3) =123*321 = 39483.

Mathematica

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 *)

Crossrefs

Cf. A078264.

Sequence in context: A047831 A076013 A180886 * A289293 A183507 A203385

Adjacent sequences: A078260 A078261 A078262 * A078264 A078265 A078266

Keyword

base,nonn

Author

Amarnath Murthy, Nov 24 2002

Extensions

More terms from Sascha Kurz, Jan 04 2003

Status

approved