cp's OEIS Frontend

A227508 Numbers n such that n! is divisible by R(n), the digit reversal of n.

%I A227508 #9 Jul 21 2013 02:24:01
%S A227508 1,2,3,4,5,6,7,8,9,10,11,12,18,19,20,21,22,23,24,25,27,29,30,31,32,33,
%T A227508 36,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,
%U A227508 61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78
%N A227508 Numbers n such that n! is divisible by R(n), the digit reversal of n.
%C A227508 Numbers n for which A004086(n) divides A000142(n).
%e A227508 12 is a member since R(12)=21 divides 12! while 13 is not a member as 31 does not divide 13!.
%p A227508 read("transforms"):
%p A227508 isA227508 := proc(n)
%p A227508     if modp(n!,digrev(n)) = 0 then
%p A227508         true;
%p A227508     else
%p A227508         false ;
%p A227508     end if;
%p A227508 end proc:
%p A227508 A227508 := proc(n)
%p A227508     if n = 1 then
%p A227508         1;
%p A227508     else
%p A227508         for a from procname(n-1)+1 do
%p A227508             if isA227508(a) then
%p A227508                 return a;
%p A227508             end if;
%p A227508         end do:
%p A227508     end if;
%p A227508 end proc: # _R. J. Mathar_, Jul 20 2013
%t A227508 Select[Range[79], Divisible[#!, FromDigits[Reverse[IntegerDigits[#]]]] &]
%Y A227508 Cf. A000142, A004086.
%K A227508 nonn,base
%O A227508 1,2
%A A227508 _Jayanta Basu_, Jul 14 2013