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A072432 Numbers n for which there are exactly eight k such that n = k + reverse(k).

%I A072432 #15 Jul 12 2019 17:46:42
%S A072432 88,808,828,848,868,888,908,928,948,968,988,1131,1151,1171,1191,1211,
%T A072432 1231,1251,1271,1291,1771,2211,2332,3652,4114,5874,8008,9988,12991,
%U A072432 15125,16885,17071,17271,17347,17471,17671,17871,18071,18271,18471
%N A072432 Numbers n for which there are exactly eight k such that n = k + reverse(k).
%C A072432 Subsequence of A067030. First term is A072041(8).
%C A072432 Contains 8*10^k+8 for all k>=1. - _Robert Israel_, Jul 12 2019
%H A072432 Robert Israel, <a href="/A072432/b072432.txt">Table of n, a(n) for n = 1..673</a>
%H A072432 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%e A072432 88 = k + reverse(k) for k = 17, 26, 35, 44, 53, 62, 71, 80.
%p A072432 N:= 10^5:
%p A072432 revdigs:= proc(n) local L, i;
%p A072432   L:= convert(n, base, 10);
%p A072432   add(L[-i]*10^(i-1), i=1..nops(L))
%p A072432 end proc:
%p A072432 V:= Vector(N):
%p A072432 for x from 1 to N do
%p A072432   v:= x + revdigs(x);
%p A072432   if v <= N then V[v]:= V[v]+1 fi
%p A072432 od:
%p A072432 select(t -> V[t]=8, [$1..N]); # Robert Israel, Jul 12 2019
%t A072432 krk8Q[n_]:=Count[Range[n-1],_?(#+FromDigits[Reverse[ IntegerDigits[#]]] ==n&)]==8; Select[Range[20000],krk8Q]  (* _Harvey P. Dale_, Apr 02 2011 *)
%o A072432 (ARIBAS) var n,k,c,i,rev: integer; st,nst: string; end; m := 8; for n := 0 to 18800 do k := n div 2; c := 0; while k <= n and c < m + 1 do st := itoa(k); nst := ""; for i := 0 to length(st) - 1 do nst := concat(st[i],nst); end; rev := atoi(nst); if n = k + rev then inc(c); if k mod 10 <> 0 and k <> rev then inc(c); end; end; inc(k); end; if c = m then write(n,","); end; end;
%Y A072432 Cf. A067030, A072041.
%K A072432 base,nonn
%O A072432 1,1
%A A072432 _Klaus Brockhaus_, Jun 17 2002
%E A072432 Offset changed by _Robert Israel_, Jul 12 2019