A072434 Numbers n for which there are exactly ten k such that n = k + reverse(k).

1111, 1991, 2442, 3542, 5115, 6875, 11011, 14124, 15884, 17457, 18557, 19008, 19091, 19291, 19491, 19691, 19891, 20091, 20291, 20491, 20691, 20891, 24042, 24242, 24442, 24642, 24842, 25042, 25242, 25442, 25642, 25842, 34142, 34342

Offset: 1

Author

Klaus Brockhaus, Jun 17 2002

Keywords

• base
• nonn

Comments

Subsequence of A067030. First term is A072041(10).

Contains 11*10^k+11, 19*10^k+91, 24*10^k+42, 51*10^k+15 for all k>=2. - Robert Israel, Jul 12 2019

Examples

			2442 = k + reverse(k) for k = 1041, 1131, 1221, 1311, 1401, 2040, 2130, 2220, 2310, 2400.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..450
• Index entries for sequences related to Reverse and Add!

Crossrefs

Cf. A067030, A072041.

Programs

ARIBAS

var n,k,c,i,rev: integer; st,nst: string; end; m := 10; for n := 0 to 35000 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;

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]=10, [$1..N]); # Robert Israel, Jul 12 2019

Extensions

Offset changed by Robert Israel, Jul 12 2019