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A078263
Product of the forward and reverse concatenations of 1 to n.
2
1, 252, 39483, 5332114, 670592745, 80779853376, 9449772114007, 1082152022374638, 121932631112635269, 135650052221140070110, 1371589685334334871208531, 14951973660666886818972704952
OFFSET
1,2
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
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 24 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 04 2003
STATUS
approved