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A083971
Reverse of k concatenated with k, divided by k, where k = A083970(n).
2
11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 101, 176, 341, 451, 11, 101, 176, 209, 11, 101, 176, 11, 101, 121, 176, 11, 101, 11, 101, 11, 77, 101, 11, 101, 11, 101, 11, 1001, 101, 1001, 176, 1001, 4169, 1001, 1751, 1001, 341, 1001, 1001, 3401, 5126, 1001, 451, 1001, 1001, 4501, 11, 1001, 1001
OFFSET
1,1
LINKS
FORMULA
Note that when n is a palindrome, R(n)=n, so R(n) concat n = (10^d)n + n, where d is the number of digits of n, and R(n) is the reverse of n. Dividing by n, we obtain (R(n) concat n)/n = 10^d + 1. - Sam Alexander, Oct 21 2003; edited by Kevin Southwick, Jul 26 2015
MAPLE
f:= proc(n) local L, m, i, v;
L:= convert(n, base, 10);
m:= nops(L);
v:= add(10^(2*m-i)*L[i], i=1..m)/n+1;
if v::integer then v else NULL fi
end proc:
map(f, [$1..1000]); # Robert Israel, Jul 26 2015
MATHEMATICA
Select[ Range[ 250 ],
Divisible[
FromDigits[
Flatten[ { Reverse[ IntegerDigits[ # ] ], IntegerDigits[ # ] } ] ], # ] & ];
Table[ FromDigits[
Flatten[ { Reverse[ IntegerDigits[ tmp ] ], IntegerDigits[ tmp ] } ] ] /
tmp, {tmp, A083970} ]
(* Kevin Southwick, Jul 26 2015 *)
CROSSREFS
Sequence in context: A010850 A317244 A113587 * A240453 A052192 A110733
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 21 2003
EXTENSIONS
Corrected and extended by Sam Alexander, Oct 21 2003
Name edited by Charles R Greathouse IV, Aug 05 2015
STATUS
approved