cp's OEIS Frontend

A072433 Numbers n for which there are exactly nine k such that n = k + reverse(k).

%I A072433 #12 Jul 12 2019 17:46:23
%S A072433 99,110,121,909,929,949,969,989,1009,1010,1029,1030,1049,1050,1069,
%T A072433 1070,1089,1090,1110,1130,1150,1170,1190,1881,2101,3223,4763,9009,
%U A072433 10010,10989,11990,16236,17776,18081,18281,18481,18681,18881,18898
%N A072433 Numbers n for which there are exactly nine k such that n = k + reverse(k).
%C A072433 Subsequence of A067030. First term is A072041(9).
%C A072433 Contains 9*10^k+9 for k>=1 and 10^k+10 for k>=2. - _Robert Israel_, Jul 12 2019
%H A072433 Robert Israel, <a href="/A072433/b072433.txt">Table of n, a(n) for n = 1..422</a>
%H A072433 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%e A072433 99 = k + reverse(k) for k = 18, 27, 36, 45, 54, 63, 72, 81, 90.
%p A072433 N:= 10^5:
%p A072433 revdigs:= proc(n) local L,i;
%p A072433   L:= convert(n,base,10);
%p A072433   add(L[-i]*10^(i-1),i=1..nops(L))
%p A072433 end proc:
%p A072433 V:= Vector(N):
%p A072433 for x from 1 to N do
%p A072433   v:= x + revdigs(x);
%p A072433   if v <= N then V[v]:= V[v]+1 fi;
%p A072433 od:
%p A072433 select(t -> V[t]=10, [$1..N]); # _Robert Israel_, Jul 12 2019
%o A072433 (ARIBAS) var n,k,c,i,rev: integer; st,nst: string; end; m := 9; for n := 0 to 19500 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 A072433 Cf. A067030, A072041.
%K A072433 base,nonn
%O A072433 1,1
%A A072433 _Klaus Brockhaus_, Jun 17 2002
%E A072433 Offset changed by _Robert Israel_, Jul 12 2019