A072429 Numbers n for which there are exactly five k such that n = k + reverse(k).

55, 154, 505, 525, 545, 565, 585, 605, 625, 645, 665, 685, 1414, 1434, 1441, 1454, 1474, 1494, 1514, 1534, 1554, 1574, 1594, 2541, 5005, 6985, 14014, 14041, 14241, 14441, 14641, 14841, 15041, 15241, 15441, 15641, 15841, 15994, 18458, 19558

Offset: 1

Author

Klaus Brockhaus, Jun 17 2002

Keywords

• base
• nonn

Comments

Subsequence of A067030. First term is A072041(5).

Contains 5*(10^k+1) for k>=1. - Robert Israel, Jul 12 2019

Examples

			55 = k + reverse(k) for k = 14, 23, 32, 41, 50; 1441 = k + reverse(k) for k = 1040, 1130, 1220, 1310, 1400.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..254
• 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 := 5; for n := 0 to 24600 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]=5, [$1..N]); # Robert Israel, Jul 12 2019