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A105179 Numbers having in decimal representation the same final digit as their largest proper divisor has; a(1) = 1.

%I A105179 #14 Nov 21 2013 12:48:40
%S A105179 1,11,15,20,25,31,40,41,45,60,61,71,75,80,100,101,105,120,121,125,131,
%T A105179 135,140,143,151,160,165,175,180,181,187,191,195,200,209,211,220,225,
%U A105179 240,241,251,253,255,260,271,275,280,281,285,300,311,315,319,320,325
%N A105179 Numbers having in decimal representation the same final digit as their largest proper divisor has; a(1) = 1.
%C A105179 A010879(A032742(a(n))) = A010879(a(n));
%C A105179 A008602 is a subsequence apart from the initial term;
%C A105179 A030430 is a subsequence.
%H A105179 Reinhard Zumkeller, <a href="/A105179/b105179.txt">Table of n, a(n) for n = 1..10000</a>
%H A105179 <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%e A105179 n=105=3*35 and 105 == 35 modulo 10, therefore 105 is a term.
%t A105179 Join[{1},Select[Range[2,400],Last[IntegerDigits[Divisors[#][[-2]]]] == Last[IntegerDigits[#]]&]]  (* _Harvey P. Dale_, Apr 21 2011 *)
%o A105179 (PARI) lpf(n)=factor(n)[1,1]
%o A105179 is(n)=if(n%2, n%15==0||n%25==0||n==1||lpf(n)%5==1, n%20==0) \\ _Charles R Greathouse IV_, Jan 02 2013
%o A105179 (Haskell)
%o A105179 a105179 n = a105179_list !! (n-1)
%o A105179 a105179_list = 1 : filter (\x -> a010879 (a032742 x) == a010879 x) [2..]
%o A105179 -- _Reinhard Zumkeller_, Jan 10 2013
%K A105179 nonn,base
%O A105179 1,2
%A A105179 _Reinhard Zumkeller_, Apr 29 2005