OFFSET
1,1
LINKS
EXAMPLE
22 belongs to the sequence since 11 + 11 = 22 and 20 + 2 = 22 (k = {11, 20}); 33 belongs to the sequence since 12 + 21 = 33, 21 + 12 = 33 and 30 + 3 = 33 (k = {12, 21, 30}).
MAPLE
reverse:= proc (d) local n, m; m:=0; n:=d; while n>0 do m:=m*10+(n mod 10); n:=(n-(n mod 10))/10; od; m; end; P:={}; P2:={}; for i to 5000 do; if i>0 then; r:=i+reverse(i); rat:={r}; if P intersect rat = {} then P:=P union rat else P2:=P2 union rat fi; fi; od; P2;
# Maple program from N. J. A. Sloane, Mar 07 2016. Assumes digrev (from the "transforms" file) is available:
M:=1000; b := Array(1..M, 0);
for n from 1 to M do
t1:=n+digrev(n);
if t1 <= M then b[t1]:=b[t1]+1; fi;
od:
ans:=[];
for n from 1 to M do
if b[n]>=2 then ans:=[op(ans), n]; fi; od:
ans;
MATHEMATICA
M = 10^3; digrev[n_] := IntegerDigits[n] // Reverse // FromDigits; Clear[b]; b[_] = 0; For[n = 1, n <= M, n++, t1 = n + digrev[n]; If[t1 <= M, b[t1] = b[t1] + 1]]; A096768 = Reap[For[n = 1, n <= M, n++, If[b[n] >= 2, Sow[n]]]][[2, 1]] (* Jean-François Alcover, Oct 01 2016, after N. J. A. Sloane's Maple code *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Chuck Seggelin (seqfan(AT)plastereddragon.com), Jul 08 2004
STATUS
approved