A072435 Numbers n for which there are exactly twelve k such that n = k + reverse(k).

2552, 3333, 3432, 4224, 4653, 5764, 6116, 7876, 13123, 14883, 15235, 16346, 16775, 17567, 17666, 18447, 25052, 25252, 25452, 25652, 25852, 26052, 26252, 26452, 26652, 26852, 33033, 33132, 33233, 33332, 33433, 33532, 33633, 33732, 33833

Offset

1,1

Comments

Subsequence of A067030. First term is A072041(12).

Includes 25*10^k+52, 33*10^k+33, 42*10^k+24 and 61*10^k+16 for k >= 2. - Robert Israel, Jul 12 2019

Links

Robert Israel, Table of n, a(n) for n = 1..896

Index entries for sequences related to Reverse and Add!

Example

2552 = k + reverse(k) for k = 1051, 1141, 1231, 1321, 1411, 1501, 2050, 2140, 2230, 2320, 2410, 2500.

Maple

N:= 10^5:
revdigs:= proc(n) local L, i;
  L:= convert(n, base, 10);
  add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
V:= Vector(N):
for x from 1 to N do
  v:= x + revdigs(x);
  if v <= N then V[v]:= V[v]+1 fi;
od:
select(t -> V[t]=12, [$1..N]); # Robert Israel, Jul 12 2019

Mathematica

Module[{nn=40000}, Select[Tally[Table[n+IntegerReverse[n], {n, nn}]], #[[2]] == 12&&#[[1]]<nn&]][[All, 1]]//Sort(* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 25 2020 *)

Prog

(ARIBAS) var n, k, c, i, rev: integer; st, nst: string; end; m := 12; for n := 0 to 34200 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;

Crossrefs

Cf. A067030, A072041.

Sequence in context: A307473 A327771 A035876 * A050413 A050544 A185516

Adjacent sequences: A072432 A072433 A072434 * A072436 A072437 A072438

Keyword

base,nonn

Author

Klaus Brockhaus, Jun 17 2002

Status

approved