A095249 Reverse concatenation of first n positive integers modulo forward concatenation of first n positive integers.

0, 9, 75, 619, 4941, 37041, 246919, 1234575, 9, 10987654321, 1110987654321, 121110987654321, 775432077543108, 178553219976533007, 27956332009875522906, 3805734210999774512805, 481583522109989673502704, 58259362312008979572492603, 6836037241301907969471482502

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..375

Formula

a(n) = A000422(n) mod A007908(n). - Michel Marcus, Nov 19 2018

Example

a(4) = 619 = 4321 mod 1234.

Maple

a:= n-> irem(parse(cat(n-i$i=0..n-1)), parse(cat(i$i=1..n))):
seq(a(n), n=1..20);  # Alois P. Heinz, Nov 19 2018

Mathematica

r = f = ""; Do[r = ToString[n] <> r; f = f <> ToString[n]; Print[Mod[ToExpression[r], ToExpression[f]]], {n, 1, 30}] (* Ryan Propper, Aug 26 2005 *)
nn=30; Module[{r, f}, Table[f=Flatten[IntegerDigits/@Range[n]]; r=Flatten[ IntegerDigits/@Range[n, 1, -1]]; Mod[FromDigits[r], FromDigits[f]], {n, nn}]] (* Harvey P. Dale, Mar 04 2013 *)

Crossrefs

Cf. A000422, A007908.

Sequence in context: A281804 A210045 A125397 * A190983 A254664 A223204

Adjacent sequences: A095246 A095247 A095248 * A095250 A095251 A095252

Keyword

base,nonn

Author

Amarnath Murthy, Jun 17 2004

Extensions

Corrected and extended by Ryan Propper, Aug 26 2005

Status

approved