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A096768
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Numbers n of the form k + reverse(k) for two or more values of k.
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2
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22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132, 143, 154, 165, 176, 187, 202, 222, 242, 262, 282, 302, 303, 322, 323, 342, 343, 362, 363, 382, 383, 403, 404, 423, 424, 443, 444, 463, 464, 483, 484, 504, 505, 524, 525, 544, 545, 564, 565, 584, 585, 605, 606
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OFFSET
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1,1
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LINKS
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EXAMPLE
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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}).
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MAPLE
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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;
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MATHEMATICA
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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 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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Chuck Seggelin (seqfan(AT)plastereddragon.com), Jul 08 2004
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STATUS
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approved
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