login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Least palindromic multiple of concatenation n,n-1,n-2,...3,2,1.
1

%I #14 Sep 25 2019 04:24:11

%S 1,252,180081,855558,335323533,1072288822701,1338059508331,

%T 770589909985077,97777777779,98888888889,1109887655445567889011,

%U 739760991261414162199067937,33436553118011488411081135563433,4447899705293460330643925079987444,551190490170920715517029071094091155

%N Least palindromic multiple of concatenation n,n-1,n-2,...3,2,1.

%C a(12) > 10^25. - _Donovan Johnson_, Mar 28 2011

%t f[n_] := Block[{k = 1, p = FromDigits[ Flatten[ IntegerDigits /@ Range[n, 1, -1]]]}, While[k p != FromDigits[ Reverse[ IntegerDigits[k p]]], k++ ]; k p]; Table[ f[n], {n, 11}] (* _Robert G. Wilson v_ *)

%Y Cf. A109924.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Jul 18 2005

%E Edited, corrected and extended (a(3) - a(10)) by _Robert G. Wilson v_, Jul 21 2005

%E a(11) from _Donovan Johnson_, Mar 28 2011

%E a(12)-a(15) from _Giovanni Resta_, Sep 23 2019