cp's OEIS Frontend

A072430 Numbers n for which there are exactly six k such that n = k + reverse(k).

%I A072430 #9 Jul 12 2019 20:18:44
%S A072430 66,143,606,626,646,666,686,706,726,746,766,786,1313,1333,1353,1373,
%T A072430 1393,1413,1433,1453,1473,1493,1551,2222,2431,3113,3762,4873,6006,
%U A072430 7986,13013,14993,15051,15251,15451,15651,15851,16051,16126,16251,16451
%N A072430 Numbers n for which there are exactly six k such that n = k + reverse(k).
%C A072430 Subsequence of A067030. First term is A072041(6).
%C A072430 Includes 6*(10^k+1) for k >= 1. - _Robert Israel_, Jul 12 2019
%H A072430 Robert Israel, <a href="/A072430/b072430.txt">Table of n, a(n) for n = 1..628</a>
%H A072430 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a>
%e A072430 66 = k + reverse(k) for k = 15, 24, 33, 42, 51, 60; 626 = k + reverse(k) for k = 115, 214, 313, 412, 511, 610.
%p A072430 N:= 10^5:
%p A072430 revdigs:= proc(n) local L, i;
%p A072430   L:= convert(n, base, 10);
%p A072430   add(L[-i]*10^(i-1), i=1..nops(L))
%p A072430 end proc:
%p A072430 V:= Vector(N):
%p A072430 for x from 1 to N do
%p A072430   v:= x + revdigs(x);
%p A072430   if v <= N then V[v]:= V[v]+1 fi;
%p A072430 od:
%p A072430 select(t -> V[t]=6, [$1..N]); # Robert Israel, Jul 12 2019
%o A072430 (ARIBAS) var n,k,c,i,rev: integer; st,nst: string; end; m := 6; for n := 0 to 17500 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 A072430 Cf. A067030, A072041.
%K A072430 base,nonn
%O A072430 1,1
%A A072430 _Klaus Brockhaus_, Jun 17 2002
%E A072430 Offset changed to 1 by _Robert Israel_, Jul 12 2019